Table-like magnetocaloric effect due to field induced inter-cluster interactions in Eu0.5Sr0.5MnO3-EuMnO3 composites

Abstract

Abstract The table-like behavior of the magnetic entropy change is generally observed in rare-earth-based alloys (e.g. La(Fe,Si) 13 , Gd 50 Co 45 Fe 5 , Gd 56 Ni 15 Al 27 Zr 2 , Gd ( 1 − x − y ) Co x Al y etc). Here, we report similar table-like behavior in a bulk perovskite Eu 0.5 Sr 0.5 MnO 3 –EuMnO 3 composite system with a working temperature span of ∼80 K for a field change of ∼70 kOe. AC susceptibility and time-dependent DC magnetization relaxation measurements confirm the presence of interacting ferromagnetic clusters with a Vogel–Fulcher freezing temperature of T 0 ∼ 42.7 K. The Langevin function fittings of the isothermal magnetization curves show a non-monotonous variation of cluster size with temperature. We propose a model for the high-field dependency of the ferromagnetic cluster coupling in the composite system. This widens the transition temperature region of long-range order formation and hence gives rise to the table-like magnetocaloric effect in Eu 0.5 Sr 0.5 MnO 3 –EuMnO 3 composite systems.