Critical behavior and magnetic entropy change in Nd0.7Sr0.1Ba0.1Ca0.1MnO3−δ perovskite manganite

Abstract

The aim of our study was to investigate the critical exponents of Nd0.7Sr0.1Ba0.1Ca0.1MnO3−δ material around its paramagnetic to ferromagnetic phase transition. Reliable critical exponents i.e. β=0.355, γ=1.329, and δ=4.867 at the critical temperature TC=117K were refined using modified Arrott plot and Kouvel–Fisher methods. The critical exponent δ=4.760±0.129 was further separately determined from the isothermal magnetization data. Finally these critical exponents fulfill the Widom scaling relation δ=1+γ/β. Based on these analysis, the magnetization–field–temperature (M–H–T) data around TC collapses into two independent curves obeying the single scaling equation M(H,ε)=|ε|βf±(H/|ε|β+γ), with ε=(T−TC)/TC is the reduced temperature. Once again, the critical exponents are confirmed by the field dependence of the magnetic entropy change relation ∆SM|T=TC ∞Hn with n=1+(β−1)/(β+1). The obtained critical exponents for Nd0.7Sr0.1Ba0.1Ca0.1MnO3−δ manganite are in accordance with the prediction of the 3D-Heisenberg model with short-range magnetic interactions. The temperature dependence of specific heat and magnetic entropy change ΔSM further supports second order PM–FM phase transition and shed light the A-site-disordered perovskite effect on the magnetocaloric properties.