ESR STUDY OF GD2BACUO5

An ESR study was performed on bulk and powder specimens of Gd2BaCuO5 i n the temperature range from 77 to 473 K. Gd3+ spins exhibit paramagne tic properties above the Neel temperature of 12 K, but Cu2+ spins exhi bit weak antiferromagnetic order even at room temperature. Superparama gnetism of Cu2+ appears in powder specimens with particle dimensions o f several mu m. The magnetic susceptibilities of Gd3+ and Cu2+ were de termined separately. Further, Gd3+ and Cu2+ spins interact weakly with each other. The temperature variation of the susceptibility of Gd3+ d eviates a little from that in a Curie-Weiss law.