2005/05/02 by U. K. Goutam, Goutam, U. K., P. K. Siwach +9
Materials Science · Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Advanced Thermoelectric Materials and Devices #FOS: Physical sciences #Magnetic and transport properties of perovskites and related materials #Materials Science (cond-mat.mtrl-sci) #Strongly Correlated Electrons (cond-mat.str-el) #cond-mat.mtrl-sci #cond-mat.str-el
paper · pdf · doi:10.48550/arxiv.cond-mat/0505034
21 pages, 8 figures and 2 tables
arxiv created 2005/05/02 · openalex publication_date 2005/05/02 · arxiv updated 2009/12/01 · openalex created_date 2019/06/27 · openalex updated_date 2026/07/28
In this study we report the effect of sintering temperature on the low field magnetotransport properties of La0.7Ca0.3MnO3 manganite synthesized through polymeric precursor route. The La0.7Ca0.3MnO3 has been sintered at 600oC (S6), 700oC (S7), 800oC (S8), 900oC (S9) and 1000oC (S10). XRD confirms that phase formation starts at 600oC. All the samples are single phasic having orthorhombic unit cell. The lattice parameters decrease on lowering the sintering temperature (TS). The crystallite as well as particle size also show strong dependence on the sintering temperature. All the samples possess insulator-metal (TIM) as well as paramagnetic-ferromagnetic (TC) transitions. The TC shows a small variation [274K (S10) to 256K (S6)] as a function of sintering temperature whereas the TIM goes down from 267K (S10) to 138K (S6), a strong decrease of 129K. This TC-TIM discrepancy is due to the fact that whereas the former is an intrinsic characteristic, the latter depends strongly on the extrinsic factors e.g. synthesis conditions grain boundaries and associated disorders. For all the samples MR shows strong dependence on TS. The MR increases on lowering the temperature as well as on increasing the field with the occurrence of an intrinsic contribution around TC. These variations of MR for all the samples have been explained in terms of the microstructural variations and spin-polarized tunneling at low temperatures.