Magnetocaloric effect in $La_{1-x}Na_{x}SrMn_{2}O_{5+\delta}$ (with x = 0.1 , 0.2 and 0.3)

Abstract

The present paper is aimed to analyze the effects of sodium substitution on the magnetic entropy change between \(La_{0.9}Na_{0.1}SrMn_{2}O_{5+\delta}\) and \(La_{0.8}Na_{0.2}SrMn_{2}O_{5+\delta}\) polycrystalline samples. Evaluation of the potential magnetocaloric effects is sought through identifying the magnetic entropy change \( \Delta S_{M}\), which was basically determined from the magnetic field dependences of magnetization at different temperatures \( M(H,T)\) near \( T_{C}\). Interestingly, the substitution of a small amount of Na in \(La_{1-x}Na_{x}SrMn_{2}O_{5+\delta}\) nanocrystalline samples (with \( x=0.1\), 0.2 and 0.3) reduced the maximum magnetic entropy \( \vert\Delta S_{Max}^{M}\vert\) from 2.2 J kg-1K-1 (for \( x=0.1\) to 0.8 Jkg-1K-1 (for \( x=0.3\) for a field change \( \Delta H=5\) T. The relative cooling power (RCP) decreases with increasing Na content reaching 53.13J kg^-1 for \( x=0.3\) (\( \Delta H=5\) T), respectively.