Magneto Transport of high TCR (temperature coefficient of resistance) La2/3Ca1/3MnO3: Ag Polycrystalline Composites

TL;DR

This study demonstrates that adding silver to La2/3Ca1/3MnO3 enhances its magneto-transport properties, notably increasing TCR and MR near room temperature, due to improved microstructure and grain connectivity.

Contribution

The paper reports a novel enhancement of TCR and magneto-resistance in La2/3Ca1/3MnO3:Ag composites, with significant improvements at room temperature and above.

Findings

TCR near TFM increased up to 15% with Ag addition.

Magneto-resistance reached up to 60% above 300 K in high magnetic fields.

Silver addition improved grain size and connectivity, enhancing physical properties.

Abstract

We report the synthesis, (micro)structural, magneto-transport and magnetization of polycrystalline La2/3Ca1/3MnO3:Agx composites with x = 0.0, 0.1, 0.2, 0.3 and 0.4. The temperature coefficient of resistance (TCR) near ferromagnetic (FM) transition is increased significantly with addition of Ag. The FM transition temperature (TFM) is also increased slightly with Ag addition. Magneto-transport measurements revealed that magneto-resistance MR is found to be maximum near TFM. Further the increased MR of up to 60% is seen above 300 K for higher silver added samples in an applied field of 7 Tesla. Sharp TCR is seen near TFM with highest value of up to 15 % for Ag (0.4) sample, which is an order of magnitude higher than as for present pristine sample and best value yet reported for any polycrystalline LCMO compound. Increased TCR, TFM and significant above room temperature MR of La2/3Ca1/3MnO3:Agx composites is explained on the basis of improved grains size and connectivity with silver addition in the matrix. Better coupled FM domains and nearly conducting grain boundaries give rise to improved physical properties of the La2/3Ca1/3MnO3 manganites.