Abstract
Temperature-dependent DC electrical resistivity of polycrystalline samples with orthorhombic perovskite structure Gd0.7Ca0.3Mn1−x Cr x O3 (x = 0.0–0.5) has been reported. The samples were prepared by the solid-state reaction method. The resistivity of all the samples indicates a semiconducting nature. In the high-temperature region, the electrical conduction process follows the small polaron hopping (SPH) mechanism showing exponential variation of resistivity with temperature. The activation energy increases with Cr concentration. The low-temperature resistivity data follows Mott’s ln(ρT −1/2)∼T −1/4 law of variable-range hopping (VRH) conduction mechanism. The estimated values of hopping distances (R) and hopping energies (W) of the samples start to increase with increasing Cr concentrations from and above x = 0.5 and satisfy essential conditions of the Mott VRH, i.e., αR>> 1 (α = inverse localization length) and W/ K B T>> 1. This signifies that evaluation of these parameters being logical and the effect can be attributed to high density of doping which introduces simultaneously potential disorder and localized states. The magnetic field-dependent magnetoresistance has been explained by a phenomenological model considering spin-polarized tunneling at grain boundaries in the samples.
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Moreira, J.A., Almeida, A., Chaves, M. R., Kreisel, J., Oliveira, J., Carpinteiro, F., Tavares, P.B.: Magnetically-induced lattice distortions and ferroelectricity in magnetoelectric GdMnO3. J. Phys.: Condens. Matter 24, 436002 (2012)
Kimura, T., Lawes, G., Goto, T., Tokura, Y., Ramirez, A.P.: Magnetoelectric phase diagrams of orthorhombic RMnO3 (R = Gd, Tb, and Dy). Phys. Rev. B 71, 224425 (2005)
Khan, M.H., Pal, S., Bose, E.: Nature of temperature- and magnetic-field-dependent conduction mechanism in electron-doped Ca0.85 R0.15MnO3 (R = Pr, La) manganites. Phys. Status Solidi B 251, 559 (2014)
Biswas, S., Khan, M.H., Pal, S., Bose, E.: The effects of Mn substitution on magnetization reversal properties in Gd0.7Ca0.3MnO3. J. Supercond. Novel Magn. 27, 463 (2014)
Cox, D.E., Radaelli, P.G., Marezio, M., Cheong, S.W.: Structural changes, clustering, and photoinduced phase segregation in Pr0.7Ca0.3MnO3. Phys. Rev. B 57, 3305 (1998)
Markovich, V., Jung, G., Wisniewski, A., Mogilyansky, D., Puzniak, R., Kohn, A., Wu, X.D., Suzuki, K., Gorodetsky, G.: Magnetic properties of electron-doped La0.23Ca0.77MnO3 nanoparticles. Nanopart. Res. 14, 1119 (2012)
Rao, C.N.R., Raveau, B.: Colossal Magnetoresistance, Charge Ordering and Related Properties and Manganese Oxides, First ed. World Scientific, Singapore (1998)
Tokura, Y.: Colossal Magnetoresistive Oxides, First ed. Gordon and Breach Science, Singapore (2000)
Ramirez, A.P.: Colossal magnetoresistance. J. Phys: Condens. Matter 9, 8171–8199 (1997)
Snyder, G.J., Booth, C.H., Bridges, F., Hiskes, R., DiCarolis, S., Beasley, M.R., Geballe, T.H.: Local structure, transport, and rare-earth magnetism in the ferrimagnetic perovskite Gd0.67 Ca0.33MnO3. Phys. Rev. B 55, 6453 (1997)
Pena, O., Bahout, M., Ghanimi, K., Duran, P., Gutierrez, D., Moure, C.: Spin reversal and ferrimagnetism in (Gd,Ca)MnO3. J. Mater. Chem. 12, 2480–2485 (2002)
Krichene, A., Solanki, P.S., Rayaprol, S., Ganesan, V., Boujelben, W., Kuberkar, D.G.: B-site bismuth doping effect on structural, magnetic and magnetotransport properties of La0.5Ca0.5Mn1−x BixO3. Ceram. Int. 41, 2637 (2015)
Lakshmi, L.S., Dorr, K., Nenkov, K., Sastry, V.S., Muller, K.H.: Charge state modification in Mn site substituted CMR manganites: strong deleterious influence on the ferromagnetic-metallic state. J. Phys.: Condens. Matter 236207, 19 (2007)
Liu, X., Xu, X., Zhang, Y.: Effect of Ti dopant on the carrier density collapse in colossal magnetoresistance material La0.7Ca0.3 Mn1−y Ti y O3. Phys. Rev. B 62, 15112 (2000)
Kimura, T., Kumai, R., Okimoto, Y., Tokura, Y.: Variation of charge-orbital correlation with Cr doping in manganites. Phys. Rev. B 62, 15021 (2000)
Cabeza, O., Long, M., Severace, C., Bari, M.A., Muirhead, C.M., Francesconi, M.G., Greaves, C.: Magnetization and resistivity in chromium doped manganites. J. Phys.: Condens. Matter 11, 2569 (1999)
Manjunatha, S.O., Rao, A., Babu, P.D., Tarachand, Okram, G.S.: Studies on magneto-resistance, magnetization and thermoelectric power of Cr substituted La0.65Ca0.35Mn1−x Cr x O3 (0 ≤x≤0.07) manganites. Physica B 475, 1–9 (2015)
Biswas, S., Khan, M.H., Pal, S., Bose, E.: Evolution of magnetic properties in Cr doped manganites Gd0.7Ca0.3Mn1−x Cr x O3(x = 0.0−0.5). J. Magn. Magn. Mater. 328, 31–34 (2013)
Rodrigues-Carvajal, J.: Recent advances in magnetic structure determination by neutron powder diffraction. Physica B 192, 55 (1993)
Coey, J.M.D., Viret, M., von Molnar, S.: Mixed-valence manganites. Adv. Phys. 48, 167–293 (1999)
Goodenough, J.B., Zhou, J.S.: Localized to itinerant electronic transitions in transition-metal oxides with the perovskite structure. Chem. Mater. 10, 2980–2993 (1998)
Androulakis, J., Migiakis, P., Giapintzakis, J.: La0.95Sr0.05CoO3: an efficient room-temperature thermoelectric oxide. Appl. Phys. Lett. 84, 1099 (2004)
Liu, Y., Qin, X.Y.: Temperature dependence of electrical resistivity for Ca-doped perovskite type Y1−x Ca x CoO3 prepared by sol–gel process. J. Phys. Chem. Solids 67, 1893–1898 (2006)
Goodenough, J.B., Wold, A., Arnott, R.J., Menyuk, N.: Relationship between crystal symmetry and magnetic properties of ionic compounds containing mn3+. Phys. Rev. 124, 373 (1961)
Sun, Y., Xu, X., Zhang, Y.: Effects of Cr doping in La0.67Ca0.33 MnO3: magnetization, resistivity, and thermopower. Phys. Rev. B 054404, 63 (2000)
Modi, A., Gaur, N.K.: Structural, electrical and magnetic phase evolution of Cr substituted GdMn1−x Cr x O3 (0 x 0.2) manganites. J. Alloys Compd. 644, 575–581 (2015)
Lu, C., Hu, N., Yang, M., Xia, S., Wang, H., Wang, J., Xia, Z., Liu, J.M.: High magnetic field phase diagram in electron-doped manganites La0.4Ca0.6Mn1−y Cr y O3. Sci. Rep. 4, 4902 (2014)
Okutan, M., Bakan, H.I., Korkmaz, K., Yakuphanoglu, F.: Variable range hopping conduction and microstructure properties of semiconducting Co-doped TiO2. Physica B 355, 176 (2005)
Tank, T.M., Bhargava, D., Sridharan, V., Samatham, S.S., Ganesan, V., Sanyal, S.P.: Influence of Mn site substitution on electrical resistivity and magnetoresistance properties of rare earth manganite. Advanced Materials Research 1047, 123–129 (2014)
Raychaudhuri, P., Nath, T.K., Nigam, A.K., Pinto, R.: A phenomenological model for magnetoresistance in granular polycrystalline colossal magnetoresistive materials: the role of spin polarized tunneling at the grain boundaries. J. Appl. Phys. 84, 2048–2052 (1998)
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This work was partially supported by DST-PURSE and DST-FIST Govt. of India.
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Pal, S., Biswas, S., Nag, R. et al. Hopping Transport and Spin-Polarized Tunneling Mechanism in Cr-Doped Gd0.7Ca0.3Mn1−x Cr x O3 (x = 0.0–0.5). J Supercond Nov Magn 30, 2505–2513 (2017). https://doi.org/10.1007/s10948-017-4023-7
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DOI: https://doi.org/10.1007/s10948-017-4023-7