Antiferromagnetic Order Observed by Submillimeter Wave ESR in Y2BaCuO5

Abstract
Antiferromagnetic order of Y 2 BaCuO 5 has been observed by submillimeter wave ESR in the frequency region from 90 to 383 GHz using pulsed magnetic field up to 16 T. Transition temperature is determined to be around 15 K using powder sample. The results suggest easy-plane type anisotropy and they are analyzed in the framework of molecular field theory. The result of the magnetization measurement is also presented.