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

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 angstrom and c=19.183 angstrom 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 T-B=76 K and a second for the ferromagnetic-paramagnetic transition is found at Curie temperature T-C=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 (-S-M), 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 T-C, the value of (-Delta SMmax) 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.