Direct and specific heat study of magnetocaloric effect in La0.845Sr0.155MnO3

Abstract

Magnetocaloric effect and specific heat of a La0.845Sr0.155MnO3 sample were measured over a temperature range of 4.2–300 K, to verify whether large entropy changes induced by magnetic field make possible the use of manganites for magnetic refrigeration and whether a magnetostrictive contribution to magnetocaloric effect is significant. Isothermal entropy change and adiabatic temperature change induced by ΔB=7 T were determined as functions of temperature. Near to the Curie temperature, TC≈234 K, they reach, respectively, ∼−6.6 J/(kg K) and ∼3.4 K, i.e., the values ∼2 and ∼4 times smaller than for Gd. Despite the presence of large magnetostriction, its contribution to magnetocaloric effect was found negligible.