Magnetic and Magnetoresistive Properties of Nanocrystalline Pr1−xAxMn1−yCoyO3 (A = Sr, Ca; x = 0.3, y = 0.5)

TL;DR: In this article, Nanocrystalline Pr1−xAxMn1−yCoyO3 samples are prepared by sol-gel method and the XRD pattern shows single phase and cubic crystal structure with a size of 3.862 nm at room temperature.

Abstract: Nanocrystalline Pr1−xAxMn1−yCoyO3 (A = Sr, Ca; x = 0.3, y = 0.5) samples are prepared by sol‐gel method. The XRD pattern show single phase and cubic crystal structure with a ( = b = c) = 3.862 nm at room temperature. The crystallite size of the samples are calculated using Scherrer formula and found to be ∼15 nm and ∼24 nm for Pr0.7Sr0.3Mn0.5Co0.5O3 and Pr0.7Ca0.3Mn0.5Co0.5O3 respectively. The SEM images show the particles are spherical in shape and average particles sizes are about ∼20 nm and ∼25 nm. The samples undergo paramagnetic to ferromagnetic transition about ∼172 K and ∼153 K. The temperature dependence of resistivity (ρ) data show insulating behaviour below 80 K and from 80 K to 300 K, the samples behave like semiconductor. Variable range hopping conduction is found to be dominating for temperatures above 80 K. The maximum magnetoresistance is found to be ∼35% and ∼24% at 100 K and it has negative sign.