Magnetic and magnetocaloric properties of Sm1-xCaxMnO3 (x=0.88) nanoparticles

We used the mechanical milling to prepare orthorhombic (Sm012Ca0.88MnO3)-Ca-. samples with the average crystallite size (d) changing from 100 to 139 nm. Their magnetic and magnetocaloric properties were then studied upon magnetization data versus the temperature and magnetic field, M(T, H). The results revealed the samples undergoing the ferromagnetic-paramagnetic (FM-PM) phase transition at the Curie temperature TC approximate to 110 K. Around this transition, the magnetic-entropy change (DSm) reaches the maxima. The maximum |Delta Sm| values are about 2-4J center dot kg(-1)center dot K-1, corresponding to relative cooling power of 35-60 J center dot kg(-1), for an applied field H = 30 kOe. The assessments based on Banerjee's criteria and constructing a universal curve for | DSm( T, H)| data indicate the samples having the nature of a secondorder phase transition. Also, the detailed analyses based on the Curie-Weiss law and magnetic-order exponent prove the existence of the Griffiths phase and magnetic inhomogeneity in the samples. These properties would be changed by changing d. (C) 2017 Elsevier B.V. All rights reserved.