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

Abstract We used the mechanical milling to prepare orthorhombic Sm 0.12 Ca 0.88 MnO 3 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 T C ≈ 110 K. Around this transition, the magnetic-entropy change (Δ S m ) reaches the maxima. The maximum |Δ S m | values are about 2–4 J·kg −1 ·K −1 , corresponding to relative cooling power of 35–60 J·kg −1 , for an applied field H = 30 kOe. The assessments based on Banerjee’s criteria and constructing a universal curve for |Δ S m ( T , H )| data indicate the samples having the nature of a second-order 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 .