Transport Properties of the Layer Manganite La_1.5Ca_1.5Mn_2-xFe_xO₇

Anjali Krishnamurthy, M. P. Sharma, Bipin K. Srivastava

.

DOI: 10.4236/wjcmp.2011.14022                

Abstract

Layered perovskite manganite ceramics with a nominal chemistry La_1.5Ca_1.5Mn_2-xFe_xO₇(x = 0.0, 0.05, 0.1, 0.3, 0.5) were prepared using sol-gel method. The manganese ions are highly mixed states of Mn³⁺ and Mn⁴⁺. It is found that the Mn³⁺/Mn⁴⁺ ratio decreases with the Fe doping content increasing. The conductivity and magnetoresistance (MR) were studied. The sample of x = 0.05 shows metal insulator transition (MIT) at 135 K. The MIT peak temperature (Tp) shifts towards higher temperature with increasing applied magnetic field. All the samples can be well fitted to the variable-range hopping (VRH) model. The maximum value of MR (%) [ρ(0) - ρ(H)]/ρ(0) × 100 for x = 0.05 is 34% (105 K, 7 kOe).

Keywords

Layered Perovskite, M-I Transition, GMR

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	R. Mahendiran, S. K. Tiwary, A. K. Raychaudhuri and T. V. Ramakrishnan, “Structure, Electron-Transport Proper- ties, and Giant Magnetoresistance of Hole-Doped LaMnO3 Systems,” Physical Review B, Vol. 53, No. 6, 1996, pp. 3348-3385. doi:10.1103/PhysRevB.53.3348
[2]	P. Mandal and B. Ghosh, “Transport, Magnetic, and Struc- tural Properties of La1-xMxMnO3 (M = Ba, Sr, Ca) for 0 ? x ? 0.20,” Physical Review B, Vol. 68, No. 1, 2003, pp. 014422(1-8). doi:10.1103/PhysRevB.68.014422
[3]	K. H. Ahn, X. W. Wu, K. Liu and C. L. Chien, “Magnetic Properties and Colossal Magnetoresistance of La(Ca)MnO3 Materials Doped with Fe,” Physical Review B, Vol. 54, No. 21, 1996, pp. 15299-15302. doi:10.1103/PhysRevB.54.15299
[4]	C. Zener, “Interaction between the d-Shells in the Transi- tion Metals. II. Ferromagnetic Compounds of Manganese with Perovskite Structure,” Physical Review, Vol. 82, No. 3, 1960, pp. 403-405. doi:10.1103/PhysRev.82.403
[5]	P.-G. de Gennes, “Effects of Double Exchange in Magne- tic Crystals,” Physical Review, Vol. 118, No. 1, 1960, pp. 141-154. doi:10.1103/PhysRev.118.141
[6]	H. Asano, J. Hayakawa and M. Matsui, “Giant Magneto- resistance of a Two-Dimensional Ferromagnet La2?2xCa1+2xMn2O7,” Applied Physics Letters, Vol. 68, No. 25, 1996, pp. 3638-3640. doi:10.1063/1.115755
[7]	M. P. Sharma, A. Krishnamurthy and B. K. Srivastava, “Ma- gnetization and M?ssbauer Study of Double Layer Pero- vskites La1.5Ca1.5FexMn2-xO7 Prepared by Sol-Gel Me- thod,” Hyperfine Interaction, Vol. 184, No. 1-3, 2008, pp. 201-206. doi:10.1007/978-3-540-78697-9_83
[8]	M. Viret, L. Ranno and J. M. D. Coey, “Magnetic Local- ization in Mixed-Valence Manganites,” Physical Review B, Vol. 55, No. 13, 1997, pp. 8067-8070. doi:10.1103/PhysRevB.55.8067
[9]	J. M. D. Coey, M. Viret, L. Ranno and K. Ounadjela, “Elec- tron Localization in Mixed-Valence Manganites,” Applied Physics Letters, Vol. 75, No. 21, 1995, pp. 3910-3913. doi:10.1103/PhysRevLett.75.3910
[10]	M. Viret, L. Ranno and J. M. D. Coey, “Colossal Magne- toresistance of the Variable Range Hopping Regime in the Manganites,” Journal of Applied Physics, Vol. 81, No. 8, 1997, pp. 4964-4971. doi:10.1063/1.365013
[11]	Y. Sun, X. Xu and Y. Zhang, “Variable-Range Hopping of Small Polarons in Mixed-Valence Manganites,” Jour- nal of Physics: Condensed Matter, Vol. 12, No. 50, 2000, pp. 10475-10481. doi:10.1088/0953-8984/12/50/309
[12]	D. Emin and T. Holstein, “Adiabatic Theory of an Elec- tron in a Deformable Continuum,” Physical Review Let- ters, Vol. 36, No. 6, 1976, pp. 323-326. doi:10.1103/PhysRevLett.36.323
[13]	M. Ziese and C. Srinitiwarawong, “Polaronic Effects on the Resistivity of Manganite Thin Films,” Physical Re- view B, Vol. 58, No. 17, 1998, pp. 11519-11525. doi:10.1103/PhysRevB.58.11519
[14]	A. Banerjee, S. Pal and B. K. Chaudhuri, “Nature of Small-Polaron Hopping Conduction and the Effect of Cr Doping on the Transport Properties of Rare-Earth Man- ganite La0.5Pb0.5Mn1?xCrxO3,” Journal of Chemical Phys- ics, Vol. 115, No. 3, 1998, pp. 1550-1558. doi:10.1063/1.1378018
[15]	D. S. Rana, C. M. Thaker, K. R. Mavani, D. G. Kuberkar, D. C. Kundaliya and S. K. Malik, “Magnetic and Trans- port Properties of (La0.7?2xEux)(Ca0.3Srx)MnO3: Effect of Simultaneous Size Disorder and Carrier Density,” Jour- nal of Applied Physics, Vol. 95, No. 9, 2004, pp. 4934- 4940. doi:10.1063/1.1667258
[16]	H. Zhu, X. J. Xu, L. Pi and Y. H. Zheng, “Two-Dimen- sional Magnetic Correlation and Transport Behavior of Layered Manganite La1.4Sr1.6Mn2-xCuxO7,” Physical Re- view B, Vol. 62, No. 10, 2002, pp. 6754-6760. doi:10.1103/PhysRevB.62.6754
[17]	W. H. Jung, “Evaluation of Mott’s Parameters for Hopping Conduction in La0.67Ca0.33MnO3 above Tc,” Journal of Ma- terials Science Letters, Vol. 17, No. 15, 1998, pp. 1317- 1319. doi:10.1023/A:1006665200481
[18]	J. W. Liu, G. Chen, Z. H. Li, W. W. An and Z. G. Zhang, “X-Ray Photoemission Spectra and the Electro-Transport Properties Studies on the Layered Manganites Sm2?2xSr1+2xMn2O7,” Journal of Alloys and Compounds, Vol. 431, No. 1-2, 2007, pp. 1-5. doi:10.1016/j.jallcom.2006.05.038