Abstract
The structure, magnetization M, resistivity ρ, thermoelectric power S, and thermal conductivity κ in La0.9Te0.1Mn1−xCoxO3 (0 ≤ x ≤ 1) have been investigated systematically. The samples with x = 0 and x = 1 have a rhombohedral lattice with space group R¯3C, while the samples with x = 0.25, 0.50, and 0.75 have an orthorhombic lattice with space group Pbnm. The samples of 0 ≤ x ≤ 0.75 undergo the paramagnetic–ferromagnetic (PM–FM) phase transition. Based on the temperature dependence of susceptibility, a combination of the high-spin (HS) state for Co2+ and the low-spin (LS) state for Co3+ can be determined. The metal–insulator transitions (MIT) observed for x = 0 sample are completely suppressed with Co-doping, and ρ(T) displays semiconducting behavior within the measured temperature region for x > 0 samples. As x ⩾ 0.25, the huge magnitude of Seebeck coefficient at low temperatures is observed, which is suggested to originate from the spin-state transition of Co3+ ions from intermediate-spin (IS) state or (HS) state to (LS) state and the configurational entropy of charge carriers enhanced by their spin and orbital degeneracy between Co2+ and Co3+ sites. Particularly, S(T) of x = 0.50 and 0.75 samples appears an anomalous peak, which is suggested to be related to the contribution of phonon drag. Similar to M(T) and ρ(T), all results of S(T) are discussed according to the variations of the structure parameters and magnetic exchange interaction caused by Co-doping. In addition, based on the analysis of the temperature dependence of S(T) and ρ(T), the transport mechanism can be determined in the different temperature region. As to thermal conduction κ(T), the changes of κ with Co-doping is suggested to come from the combined effect due to the suppression of local Mn3+O6 Jahn–Teller (JT) lattice distortion because of the substitution of non JT Co3+ ions with LS and HS states for JT Mn3+ ions, which results in the increase of κ, and the introduction of the disorder due to Co-doping, which contributes to the decrease of κ.
Similar content being viewed by others
References
S. Jin, T.H. Tiefel, M. McCormack, R.A. Fastnacht, R. Ramesh L.H. Chen: Thousandfold change in resistivity in magnetoresistive La-Ca-Mn-O films. Science 264, 413 1994
A. Asamitsu, Y. Moritomo, Y. Tomioka, T. Arima Y. Tokura: A structural phase transition induced by an external magnetic field. Nature 373, 407 1995
R. von Helmolt, J. Wecker, B. Holzapfel, L. Schultz K. Samwer: Giant negative magnetoresistance in perovskitelike La2/3Ba1/3MnOx ferromagnetic films. Phys. Rev. Lett. 71, 2331 1993
C. Zener: Interaction between the d-shells in the transition metals. II. Ferromagnetic compounds of manganese with perovskite structure. Phys. Rev. 82, 403 1951
J.B. Goodenough: Theory of the role of covalence in the perovskite-type manganites [La, M(II)]MnO3. Phys. Rev. 100, 564 1955
A.J. Millis, P.B. Littlewood B.I. Shraiman: Double exchange alone does not explain the resistivity of La1−xSrxMnO3. Phys. Rev. Lett. 74, 5144 1995
P. Mandal S. Das: Transport properties of Ce-doped RMnO3 (R= La, Pr, and Nd) manganites. Phys. Rev. B 56, 15073 1997
S. Roy N. Ali: Charge transport and colossal magnetoresistance phenomenon in La1−xZrxMnO3. J. Appl. Phys. 89, 7425 2001
G.T. Tan, S.Y. Dai, P. Duan, Y.L. Zhou, H.B. Lu Z.H. Chen: Colossal magnetoresistance behavior and ESR studies of La1−xTexMnO3 (0.04 ≤ x ≤ 0.2). Phys. Rev. B 68, 014426 2003
G.T. Tan, S.Y. Dai, P. Duan, Y.L. Zhou, H.B. Lu Z.H. Chen: Structural, electric and magnetic properties of the electron-doped manganese oxide: La1−xTexMnO3 (x = 0.1, 0.15). J. Appl. Phys. 93, 5480 2003
S.R. English, J. Wu C. Leighton: Thermally excited spin-disorder contribution to the resistivity of LaCoO3. Phys. Rev. B 65, 220407 2002
N. Gayathri, A.K. Raychaudhuri, S.K. Tiwary, R. Gundakaram, A. Arulraj C.N.R. Rao: Electrical transport, magnetism, and magnetoresistance in ferromagnetic oxides with mixed exchange interactions: A study of the La0.7Ca0.3Mn1−xCoxO3 system. Phys. Rev. B 56, 1345 1997
C.M. Srivastava, S. Banerjee, T.K. GunduRao, A.K. Nigam D. Bahadur: Evidence of spin transition and charge order in cobalt substituted La0.7Ca0.3MnO3. J. Phys.: Condens. Matter 15, 2375 2003
G.H. Zheng, Y.P. Sun, X.B. Zhu W.H. Song: Structure, magnetic, and transport properties of the Co-doped manganites in La0.9Te0.1Mn1−xCoxO3 (0 ≤ x ≤ 0.25). Solid State Commun. 137, 326 2006
D.B. Wiles R.A. Young: A new computer program for Rietveld analysis of x-ray powder diffraction patterns. J. Appl. Crystallogr. 14, 149 1981
K. Ghosh, S.B. Ogale, R. Ramesh, R.L. Greene, T. Venkatesan, K.M. Gapchup, Ravi Bathe S.I. Patil: Transition-element doping effects in La0.7Ca0.3MnO3. Phys. Rev. B 59, 533 1999
S. Satpathy, Z.S. Popovic F.R. Vukajlovic: Electronic structure of the perovskite oxides: La1−xCaxMnO3. Phys. Rev. Lett. 75, 960 1996
S. Blundell: Magnetism in Condensed Matter Oxford University Press New York 2001 272
S. de Brion, F. Ciorcas, G. Chouteau, P. Lejay, P. Radaelli C. Chaillout: Magnetic and electric properties of La1−δMnO3. Phys. Rev. B 59, 1304 1999
A.A. Taskin Y. Ando: Electron–hole asymmetry in GdBaCo2O5+x: Evidence for spin blockade of electron transport in a correlated electron system. Phys. Rev. Lett. 95, 176603 2005
L. Pi, L. Zheng Y. Zhang: Transport mechanism in polycrystalline La0.825Sr0.175Mn1−xCuxO3. Phys. Rev. B 61, 8917 2000
P. Mandal: Temperature and doping dependence of the thermopower in LaMnO3. Phys. Rev. B 61, 14675 2000
R. Ang, W.J. Lu, R.L. Zhang, B.C. Zhao, X.B. Zhu, W.H. Song Y.P. Sun: Effects of Co doping in bilayered manganite LaSr2Mn2O7: Resistivity, thermoelectric power, and thermal conductivity. Phys. Rev. B 72, 184417 2005
P.M. Chaikin G. Beni: Thermopower in the correlated hopping regime. Phys. Rev. B 13, 647 1976
W. Koshibae, K. Tsutsui S. Mackawa: Thermopower in cobalt oxides. Phys. Rev. B 62, 6869 2000
N.F. Mott E.A. Davis: Electronic Processes in Non-crystalline Materials 2 ed. Oxford University Press New York 1979 604 pp
S. Uhlenbruck, B. Buchner, R. Gross, A. Freimuth, A. Maria Leon de Guevara A. Revcolevschi: Thermopower and anomalous heat transport in La0.85Sr0.15MnO3. Phys. Rev. B 57, 5571 1998
A. Asamitsu, Y. Moritomo Y. Tokura: Thermoelectric effect in La1−xSrxMnO3. Phys. Rev. B 53, 2952 1996
R.D. Barnard: Thermoelectricity in Metals and Alloys Taylor and Francis London 1972
M. Jaime, M.B. Salamon, K. Pettit, M. Rubinstein, R.E. Treece, J.S. Horwitz D.B. Chrisey: Magnetothermopower in La0.67Ca0.33MnO3 thin films. Appl. Phys. Lett. 68, 1576 1996
I.P. Zvyagin, I.A. Kurova N.N. Ormont: Variable range hopping in hydrogenated amorphous silicon. Phys. Status Solidi C 1, 101 2004
G. Jeffrey Snyder, R. Hiskes, S. Dicarolis, M.R. Beasley T.H. Geballe: Intrinsic electrical transport and magnetic properties of La0.67Ca0.33MnO3 and La0.67Sr0.33MnO3 MOCVD thin films and bulk material. Phys. Rev. B 53, 14434 1996
A. Banerjee, S. Pal, S. Bhattacharya, B.K. Chauhuri H.D. Yang: Magnetoresistance and magnetothermoelectric power of La0.5Pb0.5Mn1−xCrxO3. Phys. Rev. B 64, 104428 2001
I.P. Zvyagin: Hopping Transport in Solids, edited by M. Pollak and B. Shklovskii (North-Holland, Amsterdam 1991 Vol. 28, Chap. 5, pp. 143–174
M. Matsukawa, M. Narita, T. Nishimura, M. Yoshizawa, M. Apostu, R. Suryanarayanan, A. Revcolevschi, K. Itoh N. Kobayashi: Anisotropic phonon conduction and lattice distortions in colossal-magnetoresistance bilayer manganite (La1−zPrz)1.2Sr1.8Mn2O7 (z= 0, 0.2, 0.4, and 0.6) single crystals. Phys. Rev. B 67, 104433 2003
Acknowledgments
This work was supported by the National Key Basic Research under Contract No. 2007CB925002, and the National Nature Science Foundation of China (Contract Nos. 10474100 and 50672099), and Director’s Fund of Hefei Institutes of Physical Science, Chinese Academy of Sciences.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Ang, R., Sun, Y.P., Zheng, G.H. et al. Magnetic, electrical, and thermal characterization of La0.9Te0.1Mn1−xCoxO3 (0 ≤ x ≤ 1). Journal of Materials Research 22, 2943–2952 (2007). https://doi.org/10.1557/JMR.2007.0379
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1557/JMR.2007.0379