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Journal of Materials Engineering and Performance

, Volume 23, Issue 8, pp 2787–2794 | Cite as

Physicochemical Properties of Spray-Deposited CoFe2O4 Thin Films

  • A. A. Bagade
  • V. V. Ganbavle
  • K. Y. Rajpure
Article

Abstract

Cobalt ferrite thin films are deposited onto quartz glass substrates by chemical spray pyrolysis technique at different substrate temperatures using ferric nitrate and cobalt nitrate as precursors. Thermogravimetric analysis (TGA) study indicates the formation of CoFe2O4 by decomposition of cobalt and ferric nitrates after 800 °C. X-ray diffraction studies reveal that annealed films are polycrystalline in nature and exhibit spinel cubic crystal structure. Crystallite size varies from 39 to 44 nm with the substrate temperatures. Direct optical band gap energy of CoFe2O4 thin films is found to be 2.57 eV. The AFM images show that roughness and grain size of the CoFe2O4 thin film are about 9 and 138 nm, respectively. The measured DC resistivity of the deposited thin films indicates that as temperature increases the resistivity decreases indicating the semiconductor nature of the films. Decrease in dielectric constant (ε′) and loss tangent (tanδ) has been observed with frequency and attains the constant value at higher frequencies. The AC conductivity of cobalt ferrite thin films increases with increase in frequency. Thus, the prepared films show normal dielectric performance of the spinel ferrite thin film. Room-temperature complex impedance spectra show the incomplete semicircles as films exhibit high resistance values at lower frequencies.

Keywords

AFM CoFe2O4 thin films dielectric properties spray pyrolysis temperature 

Introduction

Ferrites are attractive materials because of their magnetic and electrical properties, high chemical stability, and mechanical hardness. Recently, ferrite thin films are used in many applications such as magnetic recording media, sensor, and microwave device (Ref 1-3). The cobalt ferrite possesses spinel structure due to its highest magnetic anisotropy and higher magnetostriction compared to other ferrites. These properties are useful in stress sensing applications, magneto optical recording devices, etc. (Ref 4, 5). The extensive research on nanocrystalline cobalt ferrite thin films has been carried out because of their incredible applications such as gas sensor, fabrication of high frequency device, etc. (Ref 6, 7). Several methods like pulsed laser deposition (PLD) (Ref 8), RF magnetron sputtering (Ref 9), sol-gel method (Ref 10), spray pyrolysis (Ref 11), etc., have been used to prepare ferrite thin films. Among the various techniques to produce ferrite thin films, spray pyrolysis is one of the best techniques as it is simple, cost effective, and useful for large area thin films (Ref 12). Bellad and Bhosale (Ref 13) prepared CoFe2O4 ferrite thin films by spray pyrolysis technique and found that films are under compressive stress with orientation of the crystallites along (111) plane for spinel cubic crystal structure. Sayed Hassan et al. (Ref 14) studied the structural properties of spin pyrolysis-coated cobalt ferrite thin films with strong (111) preferred orientation and used these films for spin electronic devices. It is found that, the reports on growth of spinel cobalt ferrite thin film are very rare, only few reports are available on ferrites thin film prepared by spray pyrolysis method (Ref 15, 16). Ferrite thin film-based gas sensors are currently the most useful technology for gas sensing application (Ref 17, 18). Ease of fabrication, low cost, and better temperature stability of saturation magnetization of cobalt ferrites films made them attractive material in commercial point of view. Chapelle et al. (Ref 19) investigated the CO2 sensing behavior of nanocomposite spinel ferrite thin films. The response in a carbon dioxide atmosphere was measured at various concentrations, frequencies, and at different working temperatures. The results showed the highest response of 50% for a CO2 at 250 °C.

In this paper, polycrystalline CoFe2O4 thin films have been deposited onto the quartz glass substrate by spray pyrolysis technique. The as-deposited thin films were annealed at 900 °C for 4 h in ambient atmosphere and were characterized for their physicochemical properties. The effect of substrate temperature onto the film (annealed) properties like thermogravimetric, structural, optical, electrical, and dielectric has been discussed.

Experimental Procedure

The cobalt ferrite thin films were deposited onto the preheated quartz glass substrates using spray pyrolysis technique. The spray solution was prepared by using mixture of 0.1 M ferric nitrate (Fe(NO3)3·9H2O) and 0.1 M cobalt nitrate (Co(NO3)2·6H2O) in double distilled water. The resultant solution was sprayed onto preheated quartz glass substrates kept at different substrate temperatures (300, 350, 400, and 450 °C) with an interval of 50 °C. The other preparative parameters such as spray rate 4.5 mL/min, solution quantity 60 mL, and nozzle-to-substrate distance 32.5 cm were kept constant for all experiments. Compressed air was used as a carrier gas to atomize the spray.

In spray pyrolysis method, the precursor material is dissolved in a suitable solvent and then the solution is sprayed onto the preheated glass substrates maintained at a desired temperature. By spraying the mixture of metallic chlorides, nitrides with particular concentration, semiconducting films can be prepared. Spray pyrolysis unit mainly consists of spray nozzle, precursor solution, heater, temperature controller, and air compressor. Spray nozzle, made up of glass, consists of the solution tube surrounded by the glass bulb. With the application of pressure to the carrier gas, the vacuum is created at the tip of the nozzle and the solution is sucked in the solution tube. In this process, the precursor solution is atomized through a glass nozzle. The nozzle converts the solution into small droplets, known as aerosols. These aerosols are allowed to travel through thermal gradient and finally incident onto the heated glass substrates. The pyrolytic decomposition of aerosols takes place and formation of thin films with the desired properties occurs on the substrates. The properties of the thin film depend upon the spray rate, substrate temperature, carrier gas, droplet size, and also the cooling rate after deposition. The film thickness depends upon the various parameters such as distance between the spray nozzle and substrate, substrate temperature, concentration of solution, and the quantity of the sprayed solution. The advantages of spray pyrolysis techniques are large area films, need low energy for operation, doping is simple, layered coatings are easy, and thickness of the film can be controlled by changing spray parameters. Schematic diagram of typical spraying system used in the present investigation is reported by Patil in his review (Ref 20).

Thermogravimetric analysis (TGA) of the precursor powders was carried out for determination of decomposition temperature using TA Instruments model SDT Q600. The as-deposited ferrite thin films were annealed at 900 °C temperature for 4 h in ambient atmosphere. These annealed films were characterized for their physicochemical properties. To analyze the crystalline quality, phase identification, and other related parameters of annealed CoFe2O4 thin films, XRD were carried out using Bruker D2-Phaser x-ray diffractometer with CuKα (λ = 1.5406 Å) radiation recorded in ranges of 20° to 80°. Optical absorption studies were carried out using Shimadzu UV-Vis 3600 spectrophotometer. The thickness of the films was measured by AMBIOS, USA XP-I surface profiler. The surface topography was studied using INNOVA 1B3BE AFM (Bruker, USA). The DC electrical resistivity of cobalt ferrite thin films was measured by the two-probe method with a high-sensitivity Keithley electrometer (6514). The AC parameters such as capacitance (C) and dissipation factor (tanδ) of the cobalt ferrite thin films were measured using a high-precision LCR meter bridge (HP-6284A) in the frequency range 20 Hz to 1 MHz. The AC conductivity of the films was estimated from the dielectric parameters.

Results and Discussion

Thermogravimetric Analysis

In order to decide the suitable temperature for the decomposition of CoFe2O4, the thermogravimetric analysis (TGA) of the precursor powders, taken in the appropriate proportion, has been carried out. Figure 1 shows the typical thermogram of cobalt ferrite powder sample. Total weight loss of about 18.11% occurs below 300 °C which can be attributed to the decomposition of nitrate groups and the organic substance together (Ref 21). After 400 °C, slight weight loss (0.2501 mg) up to 800 °C is observed. No weight loss was observed above 800 °C which confirms the formation of stable spinel phase of cobalt ferrite. Thus, the results of TGA show the formation of CoFe2O4 stable spinel phase by decomposition of cobalt and ferric nitrates after 800 °C (Ref 22). This type of nature has been reported by Patange et al. (Ref 23). Therefore, spray-deposited thin film samples were annealed at 900 °C for 4 h in ambient atmosphere.
Fig. 1

Typical TGA thermogram of cobalt nitrate and ferric nitrate powder

X-ray Diffraction

Figure 2 shows x-ray diffraction (XRD) patterns of the annealed CoFe2O4 thin films deposited at different substrate temperatures (300, 350, 400, and 450 °C). A matching of the observed and standard “d” values of CoFe2O4 using JCPDS card no-00-002-1045 confirms the spinel cubic crystal structure of the films (Table 1). It is observed that as substrate temperature increases the crystallinity of cobalt ferrite films increases up to 400 °C and decreases with further increase in temperature. The XRD shows that some lower intensity peaks appeared in CoFe2O4 films are due to the lower film thickness (370 to 430 nm). The diffraction peaks indexed as (220), (311), (222), (400), (422), (511), and (440) also reveal the spinel cubic crystal structure of the deposited films. The crystallite size is estimated by the Scherrer’s formula (Ref 24):
$$D = \frac{0.9\uplambda }{\upbeta \,\cos \,\uptheta },$$
(1)
where D is the crystallite size, λ the wavelength of x-ray (1.5406 Å), β the full-width at half-maximum, and θ is the angle of diffraction. Crystallite size of the cobalt ferrite thin films is found between 38 and 45 nm. Crystallite size increases with increase in substrate temperature up to 400 °C and further decreases at higher substrate temperature (Table 2).
Fig. 2

X-ray diffraction patterns of annealed (900 °C) CoFe2O4 thin films, deposited at various substrate temperatures

Table 1

Comparison of standard (JCPDS-00-002-1045) and observed “d” values of annealed CoFe2O4 thin films deposited at various substrate temperatures

Standard “d” values, Å

Observed “d” values, Å

Reflection (hkl)

300 °C

350 °C

400 °C

450 °C

2.9600

2.9583

2.9554

2.9546

2.9542

(220)

2.5200

2.5230

2.5211

2.5209

2.5207

(311)

2.0900

2.0917

2.0914

2.0907

2.0910

(440)

1.6100

1.6114

1.6109

1.6111

1.6108

(511)

1.4800

1.4806

1.4806

1.4802

1.4802

(440)

Table 2

Variation of crystallite size and grain size of annealed CoFe2O4 thin films, deposited at various substrate temperatures

Substrate temperature, °C

Crystallite size by XRD (along 311), nm

Grain size from AFM, nm

300

38

101

350

41

116

400

43

138

450

45

160

The exact value of the lattice parameter has been calculated by plotting the graph of Nelson-Riley function (NRF) versus the lattice parameter for each plane. For the typical sample prepared at 400 °C the graph for NRF is shown in Fig. 3. The NRF is a function of Bragg angle θ calculated by the equation (Ref 25):
$${\text{NRF}} = \frac{1}{2}\left( {\frac{{\cos^{2} \uptheta }}{\sin \,\uptheta } + \frac{{\cos^{2} \uptheta }}{\uptheta }} \right),$$
(2)
where θ is the Bragg angle. Then by using a linear fit technique true lattice constant was determined. The linear fit straight line cuts the y-axis at the point of actual lattice parameter of the material. The values of lattice parameter are lower than that of bulk material which is due to the presence of oxygen vacancies (Ref 26). From Fig. 4 it is seen that the values of lattice constant increases with increase in substrate temperature due to internal stress developed in the film and difference in the temperature coefficient of expansion of the quartz substrate (Ref 27). It is seen that in Fig. 3 all the points do not lie on a linear fitted straight line due to strained perfect polycrystalline material. Therefore, it is necessary to determine the strain generated in the deposited films. The strain “ε” was determined by the formula (Ref 28):
$$\upbeta = \frac{\uplambda }{D\cos \uptheta } - \upvarepsilon \tan \uptheta ,$$
(3)
where β is the full width at half maximum, λ the wavelength of the x-ray, θ the Bragg angle, D the crystallite size, and ε is the stain. Figure 5 gives an idea about the generated strain (ε) for the typical (400 °C substrate temperature) sample. The strain was determined from the slope of the linear fitted line, its value is ~1.24 × 10−3. The value of strain increases up to 400 °C substrate temperature and further decreases due to the different crystallite sizes of the films.
Fig. 3

Nelson-Riley plot of lattice parameter for CoFe2O4 thin film deposited at 400 °C

Fig. 4

Variation of lattice constant of CoFe2O4 thin film with respect to substrate temperature

Fig. 5

The plot of (βcos θ)/λ vs. (sinθ)/λ for various planes of annealed (900 °C) CoFe2O4 thin film deposited at 400 °C

Atomic Force Microscopy

The three-dimensional (3D) atomic force microscopy images of CoFe2O4 thin films at different substrate temperatures (300 to 450 °C) are shown in Fig. 6. The AFM images were recorded on 1 μm × 1 μm planar contact mode. The micrographs show smooth and homogeneous morphology with spherical shaped nanostructure grains without any feature on the surface. The average grain size increases with increase in deposition temperature from 300 to 450 °C (see Table 2). Roughness of the annealed CoFe2O4 thin films is of the order of 7.23, 6.04, 8.56, and 2.86 nm. The highest surface roughness has been observed for the film deposited at 400 °C and it decreases with increase in deposition temperature.
Fig. 6

AFM images of annealed (900 °C) CoFe2O4 thin films, deposited at various substrate temperatures

Optical Properties and Thickness Measurement

Figure 7 reflects the optical transmittance spectrum of annealed CoFe2O4 thin films (annealed 900 °C) recorded at room temperature in the wavelength range of 300 to 1100 nm. The optical transmittance of a typical CoFe2O4 thin film deposited at 400 °C is 30%. The direct optical band gap energy of CoFe2O4 thin film is determined by the relation (Ref 29):
$$\alpha = \frac{{A(h\upnu - E_{\text{g}} )^{1/2} }}{h\upnu },$$
(4)
where is the photon energy and E g is the optical band gap energy. The plot of (α)2 versus is shown in inset of Fig. 7. Optical band gap is predicted by extrapolating the linear part of the plot at α = 0. It is seen that the direct optical band gap (E g) of the typical film deposited at 400 °C (film thickness 428 nm) is 2.57 eV. Band gap energy of CoFe2O4 is in good agreement with values reported by Himcinschi et al. (Ref 30). From Fig. 9 it is seen that the thickness of CoFe2O4 thin films increases, attaining a higher thickness at 400 °C substrate temperature and then decreases for higher substrate temperatures. The low thickness (370 nm) is observed at lower substrate temperature (300 °C), because this temperature may not be sufficient to decompose the sprayed droplets of Fe3+ and Co2+ ions from the solution. But at an optimized substrate temperature (400 °C), decomposition occurs at the optimum rate resulting in the terminal thickness of 428 nm being attained. The decrease in film thickness at higher substrate temperatures (450 °C) may be due to an evaporation of the solution prior to the substrate causing in less amount of residue reaching substrates resulting in decrease in thickness of the films at higher temperature. Also, thermophoretic force at higher temperature is higher and it repels the aerosol droplets causing decrease in thickness as reported earlier (Ref 31, 32).
Fig. 7

Transmittance spectra of CoFe2O4 thin film deposited at 400 °C substrate temperature. Inset shows plot of (αhν)2 vs. hν

DC Electrical Resistivity

Figure 8 shows the DC electrical resistivity of annealed cobalt ferrite thin films deposited at 300 to 450 °C substrate temperatures. The resistivity of cobalt ferrite thin films decreases with increase in temperature showing semiconductor behavior of the films. The films prepared at 400 °C exhibit relatively lower resistivity due to higher crystallinity of the films. In cobalt ferrites thin films, the resistivity was dependent on the concentration of Fe3+ ions present in the sample and substrate temperature (Ref 19).
Fig. 8

Variation of DC electrical resistivity of annealed (900 °C) CoFe2O4 thin films with temperature

The activation energy was calculated by the relation (Ref 33):
$$\uprho = \uprho_{0} \exp \left( {\frac{\Delta E}{kT}} \right),$$
(5)
where ∆E is the activation energy, ρ is resistivity at room temperature, k is Boltzmann constant, and ρ0 is resistivity at room temperature. The activation energy in the studied temperature region is of the order of 0.5 eV and does not vary much with the substrate temperature. It might be due to annealing at elevated temperature of 900 °C. The dissimilarity of resistivity of the films may be due to the variation of thickness (Fig. 9) with respect to substrate temperature.
Fig. 9

Variation in thickness of annealed (900 °C) CoFe2O4 thin films with respect to substrate temperature

Dielectric Properties

Figure 10 shows the variation of dielectric constant (ε′) of annealed (900 °C) cobalt ferrite thin films deposited at various substrate temperatures. The dielectric constant of cobalt ferrite thin films is measured over a frequency range from 20 Hz to 1 MHz which is calculated by the relation (Ref 34):
$$\upvarepsilon ' = \frac{Ct}{{\upvarepsilon_{0} A}},$$
(6)
where C is the capacitance, t the thickness of the film, A the area of cross section, and εo is the permittivity of free space (8.85 × 10−14 F/m). From Fig. 10 it is clear that the dielectric constant (ε′) decreases at lower frequencies and at higher frequencies it remains constant. The decrease in dielectric constant due to electric charge cannot follow the changes of applied electric field beyond a certain frequency. This dielectric dispersion type of interfacial polarization is attributed to the Maxwell-Wagner polarization-based Koop’s phenomenon hypothesis (Ref 35, 36). Due to the presence of Fe3+ and Fe2+ ions ferrite materials are referred as a dipolar. The orientation of polarization arising from dipoles creates rotational displacement this might be due to exchange of Fe+3 and Fe+2 ions in ferrite material. In cobalt ferrite, the Co2+ ions present in tetrahedral B-site are responsible for reductions in concentration of Fe3+ to Fe2+ ions in octahedral A-site which reduces the movement of Fe2+ to Fe3+. Therefore, polarization decreases with increase in frequency and attains a constant value beyond a certain frequency (Ref 37).
Fig. 10

Variation of room-temperature dielectric constant with frequency of annealed (900 °C) CoFe2O4 thin films deposited at various substrate temperatures

The variations in loss tangent (tanδ) with frequency of CoFe2O4 thin films for different substrate temperatures are shown in Fig. 11. At lower frequencies the value of tanδ is higher and then continuously decreases with increase in frequency. The high value of loss tangent at low frequencies is due to the higher resistance of the films. To understand the conduction mechanism, the room-temperature complex impedance spectra of CoFe2O4 thin films for different substrate temperatures are shown in Fig. 12. The real (Z′) and imaginary (Z′′) parts of impedance indicates incomplete semicircles. These observed incomplete semicircles at room temperature may be because the films exhibit high resistance values at low frequencies. Decreasing diameter of the incomplete semicircle indicates a reduction of the grain interior resistance.
Fig. 11

Variation of loss tangent with frequency of annealed (900 °C) CoFe2O4 thin films deposited at various substrate temperatures

Fig. 12

Variation of room-temperature compelex impedance spectra of annealed (900 °C) CoFe2O4 thin films

AC Conductivity

The AC conductivity (σac) was calculated using the relation (Ref 38):
$$\upsigma_{\text{ac}} = \upvarepsilon '\epsilon_{\text{o}}\omega \tan \,\updelta ,$$
(7)
where ω = 2πf is the angular frequency and tanδ is the dielectric loss tangent.
The room-temperature AC conductivity with respect to angular frequency (ω) is shown in Fig. 13. From this graph (logσac with logω2) it is clear that the AC conductivity of CoFe2O4 thin films increases linearly with increase in angular frequency (ω) which indicates that the conduction mechanism is due to diminutive interaction of electrons and atoms (Polarons). There are two types of polarons i.e., small and large polarons. In case of small polarons, the conductivity increases linearly with increase in angular frequency and in case of large polarons conductivity decreases with an increase in frequency (Ref 39). Thus, in case of CoFe2O4 thin films the diminutive interaction (small polarons) is responsible for increasing conductivity because this plot of AC conductivity is linear. From this graph it is seen that at certain frequencies conductivity decreases due to mixed polarons (small and large). Such type of frequency-dependent conduction due to small polarons is discussed by Devan et al. (Ref 40). The electrical resistivity, dielectric constant, and loss tangent vary slightly with deposition temperature as these parameters depend on stoichiometry and crystallinity of the material which vary slightly in the present case as the films were annealed at elevated temperature of 900 °C.
Fig. 13

Variation of AC conductivity with respect to frequency of CoFe2O4 thin films

Conclusions

Simple and economical chemical spray pyrolysis technique and post preparative treatment at 900 °C for 4 h were employed to synthesize the nanocrystalline CoFe2O4 thin films on quartz substrate. The TGA analysis revealed that above 800 °C CoFe2O4 demonstrate stable phase formation. XRD study confirms that the annealed films are polycrystalline in nature and exhibit spinel cubic crystal structure. AFM analysis corroborates the smooth surface morphology of the films. The band gap energy of CoFe2O4 thin films is 2.57 eV. DC resistivity measurements confirm the semiconductor nature of cobalt ferrite thin films. The dielectric constant (ε′) and loss tangent (tanδ) decrease with increase in frequency due to space charge polarization. The electrical resistivity, dielectric constant, and loss tangent vary slightly with deposition temperature. Complex impedance spectroscopy analysis of the films suggests grain interior contribution in the conduction process. The real and imaginary parts increase with substrate temperature.

Notes

Acknowledgments

Authors are very thankful to the council of scientific and industrial research (CSIR), New Delhi, for the financial support through its Project No. “03(1284)/13/EMR-II.” Also authors are very thankful to the University Grants Commission (UGC), New Delhi, for the financial support through its Project No. “41-869/2012 (SR)”. One of the author V.V. Ganbavle is thankful to University Grants Commission, New Delhi for providing financial support through UGC-BSR fellowship.

References

  1. 1.
    X. Sui and M.H. Kryder, Magnetic Easy Axis Randomly Inplane Oriented Barium Hexaferrite Thin Film Media, Appl. Phys. Lett., 1993, 63, p 1582–1584CrossRefGoogle Scholar
  2. 2.
    T. Kiyomura, Y. Maruo, and M. Gomi, Electrical Properties of MgO Insulating Layers in Spin-Dependent Tunnelling Junctions Using Fe3O4, J. Appl. Phys., 2000, 88, p 4768–4771CrossRefGoogle Scholar
  3. 3.
    A. Morisako, H. Nakanishi, M. Matsumoto, and M. Naoe, Low Temperature Deposition of Hexagonal Ferrite Films by Sputtering, J. Appl. Phys., 1994, 75, p 5969–5971CrossRefGoogle Scholar
  4. 4.
    S.D. Bhame and P.A. Joy, Magnetic and Magnetostrictive Properties of Manganese Substituted Cobalt Ferrite, J. Phys. D Appl. Phys., 2007, 40, p 3263–3267CrossRefGoogle Scholar
  5. 5.
    T. Dhakal, D. Mukherjee, R. Hyde, P. Mukherjee, M.H. Phan, H. Srikanth, and S. Witanachchi, Magnetic Anisotropy and Field Switching in Cobalt Ferrite Thin Films Deposited by Pulsed Laser Ablation, J. Appl. Phys., 2010, 107, p 053914CrossRefGoogle Scholar
  6. 6.
    F. Tudorache, P.D. Popa, M. Dobromir, and F. Iacomi, Studies on the Structure and Gas Sensing Properties of Nickel-Cobalt Ferrite Thinfilms Prepared by Spin Coating, Mater. Sci. Eng. B, 2013, 178, p 1334–1338CrossRefGoogle Scholar
  7. 7.
    A. Fujiwara, M. Tada, T. Nakagawa, and M. Abe, Permeability and Electric Resistivity of Spin-Sprayed Zn Ferrite Films for High-Frequency Device Applications, J. Magn. Magn. Mater., 2008, 320, p L67–L69CrossRefGoogle Scholar
  8. 8.
    G. Dascalu, G. Pompilian, B. Chazallon, O.F. Caltun, S. Gurlui, and C. Focsa, Femtosecond Pulsed Laser Deposition of Cobalt Ferrite Thin Films, Appl. Surf. Sci., 2013, 278, p 38–42CrossRefGoogle Scholar
  9. 9.
    J.G. Lee, K.P. Chae, and J.C. Sur, Surface Morphology and Magnetic Properties of CoFe2O4 Thin Films Grown by a RF Magnetron Sputtering Method, J. Magn. Magn. Mater., 2003, 267, p 161–167CrossRefGoogle Scholar
  10. 10.
    J. Sun, Z. Wang, Y. Wang, Y. Zhu, T. Shen, L. Pang, K. Wei, and F. Li, Synthesis of the Nanocrystalline CoFe2O4 Ferrite Thin Films by a Novel Sol-Gel Method Using Glucose as an Additional Agent, Mater. Sci. Eng. B, 2012, 177, p 269–273CrossRefGoogle Scholar
  11. 11.
    L.X. Phua, F. Xu, Y.G. Ma, and C.K. Ong, Structure and Magnetic Characterizations of Cobalt Ferrite Films Prepared by Spray Pyrolysis, Thin Solid Films, 2009, 517, p 5858–5861CrossRefGoogle Scholar
  12. 12.
    A. Sutka, G. Strikis, G. Mezinskis, A. Lusis, J. Zavickis, J. Kleperis, and D. Jakovlevs, Properties of Ni-Zn Ferrite Thin Films Deposited Using Spray Pyrolysis, Thin Solid Films, 2012, 526, p 65–69CrossRefGoogle Scholar
  13. 13.
    S.S. Bellad and C.H. Bhosale, Substrate Temperature Dependent Properties of Sprayed CoFe2O4 Ferrite Thin Films, Thin Solid Films, 1998, 322, p 93–97CrossRefGoogle Scholar
  14. 14.
    R. Sayed Hassan, N. Viart, C. Bouillet, J.L. Loison, G. Versini, J.P. Vola, O. Crégut, G. Pourroy, D. Muller, and D. Chateigner, Structural Properties of Cobalt Ferrite Thin Films Deposited by Pulsed Laser Deposition: Effect of the Reactive Atmosphere, Thin Solid Films, 2007, 515, p 2943–2948CrossRefGoogle Scholar
  15. 15.
    A. Takayama, M. Okuya, and S. Kaneko, Spray Pyrolysis Deposition of NiZn Ferrite Thin Films, Solid State Ion., 2004, 172, p 257–260CrossRefGoogle Scholar
  16. 16.
    M. Milanova, I. Koleva, R. Todorovska, J. Zaharieva, M. Кostadinov, and D. Todorovsky, Polymetallic Citric Complexes as Precursors for Spray-Pyrolysis Deposition of Thin Ferrite Films, Appl. Surf. Sci., 2011, 257, p 7821–7826CrossRefGoogle Scholar
  17. 17.
    C.L. Chow, H. Huang, W.C. Ang, H. Liu, Y. Huang, M.S. Tse, and O.K. Tan, Effect of Annealing Temperature on the Crystallization and Oxygen Sensing Property of Strontium Titanate Ferrite Sol-Gel Thin Films, Sens. Actuators B, 2013, 187, p 20–26CrossRefGoogle Scholar
  18. 18.
    K. Mukherjee and S.B. Majumder, Analyses of Response and Recovery Kinetics of Zinc Ferrite as Hydrogen Gas Sensor, J. Appl. Phys., 2009, 106, p 064912CrossRefGoogle Scholar
  19. 19.
    A. Chapelle, F. Oudrhiri-Hassani, L. Presmanes, A. Barnab, and Ph. Tailhades, CO2 Sensing Properties of Semiconducting Copper Oxide and Spinel Ferrite Nanocomposite Thin Film, Appl. Surf. Sci., 2010, 256, p 4715–4719CrossRefGoogle Scholar
  20. 20.
    P.S. Patil, Versatility of Chemical Spray Pyrolysis Technique, Mater. Chem. Phys., 1999, 59, p 185–198CrossRefGoogle Scholar
  21. 21.
    S. Briceno, H.D. Castillo, V. Sagredo, W. Bramer-Escamilla, and P. Silva, Structural, Catalytic and Magnetic Properties of Cu1−XCoXFe2O4, Appl. Surf. Sci., 2012, 263, p 100–103CrossRefGoogle Scholar
  22. 22.
    X.-M. Liu, S.-Y. Fu, H.-M. Xiao, and C.-J. Huang, Synthesis of Nanocrystalline Spinel CoFe2O4 Via a Polymer-Pyrolysis Route, Phys. B, 2005, 370, p 14–21CrossRefGoogle Scholar
  23. 23.
    S.M. Patange, S.E. Shirsath, B.G. Toksha, S.S. Jadhav, and K.M. Jadhav, Electrical and Magnetic Properties of Cr3+ Substituted Nanocrystalline Nickel Ferrite, J. Appl. Phys., 2009, 106, p 023914CrossRefGoogle Scholar
  24. 24.
    A.R. Babar, S.S. Shinde, A.V. Moholkar, C.H. Bhosale, J.H. Kim, and K.Y. Rajpure, Sensing Properties of Sprayed Antimony Doped Tin Oxide Thin Films: Solution Molarity, J. Alloys Compd., 2011, 509, p 3108–3115CrossRefGoogle Scholar
  25. 25.
    R.J. Deokate, S.M. Pawar, A.V. Moholkar, V.S. Sawant, C.A. Pawar, C.H. Bhosale, and K.Y. Rajpure, Spray Deposition of Highly Transparent Fluorine Doped Cadmium Oxide Thin Films, Appl. Surf. Sci., 2008, 254, p 2187–2195CrossRefGoogle Scholar
  26. 26.
    F. Gozuak, Y. Koseoglu, A. Baykal, and H. Kavasa, Synthesis and Characterization of CoxZn1−xFe2O4 Magnetic Nanoparticles Via a PEG-Assisted Route, J. Magn. Magn. Mater., 2009, 321, p 2170–2177CrossRefGoogle Scholar
  27. 27.
    M.R. Begam, N.M. Rao, S. Kaleemulla, M. Shobana, N.S. Krishna, and M. Kuppan, Effect of Substrate Temperature on Structural and Optical Properties of Nanocrystalline CdTe Thin Films Deposited by Electron Beam Evaporation, J. Nanoelectron. Phys., 2013, 5, p 03019Google Scholar
  28. 28.
    V.M. Nikale, S.S. Shinde, C.H. Bhosale, and K.Y. Rajpure, Physical Properties of Spray Deposited CdTe Thin Films: PEC Performance, J. Semicond., 2011, 32, p 033001CrossRefGoogle Scholar
  29. 29.
    M.A. Mahadik, S.S. Shinde, K.Y. Rajpure, and C.H. Bhosale, Photocatalytic Oxidation of Rhodamine B with Ferric Oxide Thin Films under Solar Illumination, Mater. Res. Bull., 2013, 48, p 4058–4065Google Scholar
  30. 30.
    C. Himcinschi, I. Vrejoiu, G. Salvan, M. Fronk, and A. Talkenberger, Optical and Magneto-Optical Study of Nickel and Cobalt Ferrite Epitaxial Thin Films and Submicron Structures, J. Appl. Phys., 2013, 113, p 084101CrossRefGoogle Scholar
  31. 31.
    K.Y. Rajpure, C.D. Lokhande, and C.H. Bhosale, Effect of the Substrate Temperature on the Properties of Spray Deposited Sb-Se Thin Films from Non-aqueous Medium, Thin Solid Films, 1997, 311, p 114–118CrossRefGoogle Scholar
  32. 32.
    L. Filipovic, S. Selberherr, G.C. Mutinati, E. Brunet, S. Steinhauer, A. Köck, J. Teva, J. Kraft, J. Siegert, and F. Schrank, Methods of Simulating Thin Film Deposition Using Spray Pyrolysis techniques, Microelectron. Eng., 2014, 117, p 57–66CrossRefGoogle Scholar
  33. 33.
    R.C. Kambale, P.A. Shaikh, C.H. Bhosale, K.Y. Rajpure, and Y.D. Kolekar, Studies on Magnetic, Dielectric and Magnetoelectric Behavior of (x) NiFe1.9Mn0.1O4 and (1 − x) BaZr0.08Ti0.92O3 Magnetoelectric Composites, J. Alloys Compd., 2010, 489, p 310–315CrossRefGoogle Scholar
  34. 34.
    P.P. Hankare, R.P. Patil, U.B. Sankpal, S.D. Jadhav, I.S. Mulla, K.M. Jadhav, and B.K. Chougule, Magnetic and Dielectric Properties of Nanophase Manganese-Substituted Lithium Ferrite, J. Magn. Magn. Mater., 2009, 32, p 3270–3273CrossRefGoogle Scholar
  35. 35.
    V.S. Sawant, S.S. Shinde, R.J. Deokate, C.H. Bhosale, B.K. Chougule, and K.Y. Rajpure, Effect of Calcining Temperature on Electrical and Dielectric Properties of Cadmium Stannate, Appl. Surf. Sci., 2009, 255, p 6675–6678CrossRefGoogle Scholar
  36. 36.
    A.R. Babar, S.S. Shinde, A.V. Moholkar, and K.Y. Rajpure, Electrical and Dielectric Properties of Co-precipitated Nanocrystalline Tin Oxide, J. Alloys Compd., 2010, 505, p 743–749CrossRefGoogle Scholar
  37. 37.
    A.A. Kadam, S.S. Shinde, S.P. Yadav, P.S. Patil, and K.Y. Rajpure, Structural, Morphological, Electrical and Magnetic Properties of Dy Doped Ni-Co Substitutional Spinel Ferrite, J. Magn. Magn. Mater., 2013, 329, p 59–64CrossRefGoogle Scholar
  38. 38.
    G. Kumar, S. Sharma, R.K. Kotnala, J. Shah, S.E. Shirsath, K.M. Batoo, and M. Singh, Electric, Dielectric and AC Electrical Conductivity Study of Nanocrystalline Cobalt Substituted Mg-Mn Ferrites Synthesized Via Solution Combustion Technique, J. Mol. Struct., 1051, 2013, p 336–344Google Scholar
  39. 39.
    R.P. Mahajan, K.K. Patankar, M.B. Kothale, and S.A. Patil, Conductivity, Dielectric Behaviour and Magnetoelectric Effect in Copper Ferrite-Barium Titanate Composites, Bull. Mater. Sci., 2000, 23, p 273–279CrossRefGoogle Scholar
  40. 40.
    R.S. Devan, Y.D. Kolekar, and B.K. Chougule, Effect of Cobalt Substitution on the Properties of Nickel-Copper Ferrite, J. Phys. Condens. Matter, 2006, 18, p 9809–9821CrossRefGoogle Scholar

Copyright information

© ASM International 2014

Authors and Affiliations

  • A. A. Bagade
    • 1
  • V. V. Ganbavle
    • 1
  • K. Y. Rajpure
    • 1
  1. 1.Electrochemical Materials Laboratory, Department of PhysicsShivaji UniversityKolhapurIndia

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