Giant magnetocaloric effect in magnetically frustrated EuHo2O4 and EuDy2O4 compounds

摘要: We have investigated the magnetic and magnetocaloric properties of EuHo2O4 EuDy2O4 by magnetization heat capacity measurements down to 2 K. These compounds undergo a field-induced antiferromagnetic ferromagnetic transition exhibit huge entropy change. For field change 0-8 T, maximum adiabatic temperature changes are 30 (25) J kg−1 K−1 12.7 (16) K, respectively, corresponding value refrigerant is 540 (415) J kg−1 for (EuDy2O4). parameters also remain large lowest measured even larger than that some potential refrigerants reported in same range. Moreover, these materials highly insulating no thermal hysteresis, fulfilling necessary conditions good low-temperature region.