Magnetocaloric Study of Ln₂Co₁₂P₇ (Ln = Y, Nd, and Sm)

抄録

Ln₂Co₁₂P₇ (Ln = Y, Nd, and Sm) shows a ferromagnetic transition of Co magnetic moments approximately at 150 K. To know how the Nd and Sm moments interact with the Co moments, the magnetocaloric effect of Ln₂Co₁₂P₇ was studied. For Ln = Nd and Sm, the value of the magnetic entropy change of Ln₂Co₁₂P₇ is positive below 50 K and increases with decreasing temperature. This behavior of the magnetic entropy change indicates that the Ln moments interact antiferromagnetically with the Co moments. For Ln = Sm, this is the first report to verify the antiferromagnetic interaction with the Co moments. The value of the magnetic entropy change steeply drops below 12 K for Ln = Nd and 20 K for Ln = Sm at 5 T, suggesting antiferromagnetic transitions.