Nonlinear magnetodielectric and magnetocaloric properties of double perovskite Ho2FeCoO6

We have investigated the magnetic, magneto-dielectric and magnetocaloric properties of the double perovskite (DP) compound Ho₂FeCoO₆. The Néel temperature T_N and the spin reorientation transition T_SR have been observed near 270 and 45 K respectively. At low temperature below T_SR highly nonlinear variation of the dielectric constant Δε′(H) has been observed under application of the magnetic field. At high temperature the enhancement of Δε′(H) has been observed due to grain boundaries. An extremely large hysteresis in Δε′(H) in presence of magnetic field suggests the strong irreversible electrical dipole orientation along the applied field. During the increasing and decreasing the magnetic field, Δε′(H) reached to 23% and just 1%, respectively at 300 K for the magnetic field change 3 T. The isothermal magnetic entropy change (−ΔS_m) and refrigeration cooling capacity (RCP) have been reached to 13 J/kg K and 325 J/kg respectively for 7 T magnetic field below 10 K.