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Low field magneto-transport in La_0.7Ca_0.3MnO_3-PMMA composites synthesized by polymeric precursor route

Jitendra Kumar·Rajiv K. Singh·H. K. Singh·P. K. Siwach·N. D. Kataria·Ramadhar Singh·O. N. Srivastava
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Abstract

A detailed investigation of the effect of PMMA on the structure, microstructure and magneto-transport properties of manganite La_0.7Ca_0.3MnO_3 (LCMO) is presented. LCMO-PMMA nanostructured composites have been synthesized by a unique polymeric sol-gel route, which leads to improved solubility of PMMA in the LCMO matrix. The LCMO phase is grown in the presence of varying PMMA concentration at ~500 ^0 C. This route yields single phase material and the grain size is observed to decrease slightly with increasing PMMA concentration. On increasing the PMMA concentration, T_C undergoes a small decrease, resistivity is observed to increase by two orders of magnitude, with a concomitant large decrease in T_IM, e.g., from 218 K for virgin LCMO to 108 K for 50 wt% PMMA admixed LCMO. Low field magneto-resistance measured in the temperature range 77-300 K shows considerable enhancement as a function of the PMMA concentration. These phenomena are explained by taking into account the increased intergranular disorder as a consequence of PMMA admixture.

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Jitendra Kumar, Rajiv K. Singh, H. K. Singh, P. K. Siwach, N. D. Kataria, Ramadhar Singh, O. N. Srivastava. 2005-04-22. Low field magneto-transport in La_0.7Ca_0.3MnO_3-PMMA composites synthesized by polymeric precursor route. https://arxiv.org/abs/cond-mat/0504579

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