Magnetization and specific heat measurement of the Shastry–Sutherland lattice compounds: Ln2BaPdO5 (Ln = La, Pr, Nd, Sm, Eu, Gd, Dy, Ho)

Ln2BaPdO5 (Ln = La, Pr, Nd, Sm, Eu, Gd, Dy, Ho) all crystallizes in Nd2BaZnO5 structure which is proposed to have a Shastry–Sutherland (S–S) lattice of Ln3+ ions. Ln2BaPdO5 (Ln = Nd, Sm, Gd, Dy, Ho) exhibits antiferromagnetic transitions at temperatures between 2 and 5 K. In addition, metamagnetic transitions have been observed for Ln2BaPdO5 (Ln = Nd, Dy, Ho) below 2 K. Specific heat of Ln2BaPdO5 (Ln = Ho, Dy) exhibits symmetric peaks at TN, and residual entropy below TN is negligibly small. On the contrary, specific heat of Ln2BaPdO5 (Ln = Nd, Sm, Gd) exhibits Schottky type anomalies followed by sharp peaks at TN, and residual entropy below TN is large. From these results, the applicability of the S–S model to Ln2BaPdO5 with various Ln3+ ions is proposed.