Inter comparison of the magneto transport of La2/3Ca1/3MnO3: Ag/In polycrystalline composites

摘要

In this article, we report the synthesis, magneto transport features, andmagnetization of polycrystalline La2/3Ca1/3MnO3:Agx/Inx composites with x = 0,0.1, 0.2, 0.3 and 0.4. In case of Ag the temperature coefficient of resistance(TCR) near ferromagnetic (FM) transition enhances significantly with additionof Ag. The FM transition temperature (TFM) is also increased slightly with Agdoping. Magneto-transport measurements revealed that magneto-resistance (MR) isfound to be maximum near TFM. Very sharp TCR is seen near TFM with highestvalue of up to 15 % for Ag (0.4) sample, which is an order of magnitude higherthan as for pristine sample and is the best value yet reported for anypolycrystalline LCMO compound. Increased TCR, TFM and significant above roomtemperature MR of La2/3Ca1/3MnO3:Agx composites is explained on the basis ofimproved grains size. Interestingly the La2/3Ca1/3MnO3:Inx composites behavedexactly in opposite way resulting in decreased TFM, and TCR compared topristine LCMO compound. In fact the grains morphology of LCMO:Inx composites isseen inferior to pristine LCMO which is opposite to the LCMO:Agx case.