Abstract
We report EPR and magnetization for Gd2BaNiO5 single crystals. The high-temperature susceptibility gives μeff = 7.9μB/mol Gd and ΘGd = 11 K (JGdGd/kB = 0.6 K). The coupling of 1-D Ni chains through the Gd-Ni interaction induces 3-D antiferromagnetic order with TN ⋍ 55(3) K, indicated by a divergence of the EPR linewidth. A mean field analysis gives JGd−Ni/kB = 3 K.