Antiferromagnetism of R2BaPdO5 (R = La, Nd, Pr, Sm, Eu, Gd, Dy, Ho)

The crystallographic and magnetic properties of R2BaPdO5 (R = La, Pr, Nd, Sm, Eu, Gd, Dy, Ho) were investigated. R2BaPdO5 has a tetragonal lattice (P4/mbm) and rare-earth ions make a layered structure with the ROR chain, where major ROR magnetic interaction occurs. R2BaPdO5 (R = La, Eu) showed a paramagnetic behavior with small temperature-dependent susceptibilities, indicating the non-magnetic states of Pd2+. The effective moment Peff of R2BaPdO5 (R = Pr, Nd, Gd, Dy, Ho) can be explained by gJJ(J+1) of the rare-earth ions. R2BaPdO5 (R = Nd, Sm, Gd, Dy, Ho) showed antiferromagnetism with TN between 2 and 5 K. R2BaPdO5 (R = Dy, Ho) showed metamagnetic transition at 2 K, whereas a clear metamagnetic transition was not observed for R2BaPdO5 (R = Gd, Nd). No magnetic transition was observed for Pr2BaPdO5 in spite of the Curie-Weiss-type paramagnetic behavior at higher temperatures. The saturation magnetization estimated at 2 K from the magnetization at 70 kOe was explained by taking account of Kramer's doublet for R2BaPdO5 (R = Nd, Sm, Dy) and the enhancement by the exchange interaction for Ho2BaPdO5.