Magnetocaloric Effect in the Double Perovskites Sr₂RRuO₆ (R = Dy and Tb)

抄録

We studied the magnetic entropy change (ΔS_m) of the double perovskites Sr₂RRuO₆ (R = Dy and Tb). The magnetic entropy change shows a peak near the second-order phase transition temperature (~40 K). The values of maximum −ΔS_m and relative cooling power for a magnetic-field change of 5 T are 2.41 J/(kg K) and 48 J/kg for the DyRu compound and 1.72 J/(kg K) and 36 J/kg for the TbRu compound, respectively. Strong interactions between the rare-earth and transition-metal magnetic moments shift −ΔS_m of the rare-earth moments to high temperatures. We compared the results of Sr₂RRuO₆ (R = Dy and Tb) with those of oxides possessing a giant magnetocaloric effect.