Spin-glass-like behavior and magnetocaloric properties in LaBiCaMn2O7 layered perovskite

Abstract

The polycrystalline layered perovskite sample LaBiCaMn2O7 was synthesized by the conventional solid-state reaction process. By the X-ray powder diffraction, we have investigated the structural properties. The diffraction patterns are consistent with tetragonal lattice parameters a = 3.824 A and c = 19.183 A with I4/mmm as a space group. The magnetic measurements have demonstrated that their properties are relevant two magnetic transitions: first for a spin-glass (SG) transition at blocking temperature TB = 76 K and a second for the ferromagnetic–paramagnetic transition is found at Curie temperature TC = 225 K. The analysis of the Arrot diagram has shown the appearance of two transitions to be of the second-order type. The magnetic entropy variation (− ∆SM), induced by the magnetic field, was presumed on the basis of Maxwell relation. Under a change in a magnetic field of 2 T and around TC, the value of (− $$\Delta S_{M}^{\max }$$ ) is found to be 4.17 J kg−1 K−1, and the value of RC (refrigeration capacity) is of 397 J.kg−1. It should be noted that LaCaBiMn2O7 displays a relatively prominent magnetocaloric effect at 225 K.