# Composition dependence of giant magnetoresistance in $La_{1-x}Ca_xMnO_3 (0.1\leq x\leq 0.9)$

Mahendiran, R and Mahesh, R and Raychaudhuri, AK and Rao, CNR (1995) Composition dependence of giant magnetoresistance in $La_{1-x}Ca_xMnO_3 (0.1\leq x\leq 0.9)$. In: Solid State Communications, 94 (7). pp. 515-518.

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## Abstract

We have studied the resistivity $(\varrho)$ and the magnetorbistance (MR) in sintered samples of $La_{1-x}Ca_x,MnO_3$ for $0.1\leq x \leq 0.9$ in the temperature range $4.2\leq T \leq 400K$ in magnetic fields $H\leq 6T$. We have observed giant negative magnetoresistance in the whole composition range, although the magnitude of MR depends on the level of doping,the peak in the magnitude of MR $[(\varrho(H)-\varrho(O))/\varrho(O)]$ at 6T being be as high as 90%. The magnitude of the MR generally increases as the temperature corresponding to the MR peak decreases. All the samples with $x\leq 0.5$ show a ferromagnetic transition with the temperature dependence of $\varrho$ showing a metallic behavior $(d\varrho/dT > 0)$ below the Curie temperature. The sample with 5 = 0.9 shows insulating behavior over the entire temperature range but the MR shows a peak at low temperatures.

Item Type: Journal Article Copyright of this article belongs to Elsevier. Giant magnetOresistance;Perovskite oxides Division of Chemical Sciences > Solid State & Structural Chemistry UnitDivision of Physical & Mathematical Sciences > Physics 25 Aug 2008 19 Sep 2010 04:35 http://eprints.iisc.ernet.in/id/eprint/10040