POSSIBILITY OF THERMALLY INDUCED FERROMAGNETISM IN YCo2.9Hy AND THE RELATED HYDRIDES

Abstract

An anomalous, sharp peak in the susceptibi1ity near 200 K is observed in PuNi3 type hydrides Y1−xZrxCo2.9Hy (x<0.2, y=3−4). The peak reduces with time and then disappears. The absorbed hydrogen acts to make the cobalt magnetic moment decrease. According to Misawa theory based on Fermi- liquid description, susceptibi1ity maximum, thermally induced ferromagnetism and ferromagnetism occur with increase of a parameter, interaction strength. The inhomogeneous hydrogen distribution in the crystal may form locally areas of various interaction strength, also appropriate for thermally induced ferromagnetism, which is considered to be an origin of the susceptibility peak. The magnetic studies of Y(FexCo1−x)2.9Hy (y=3−4) were performed and the varation from the Pauli paramagnetism of anomalous peak to the ferommagnetism with increasing Fe concentration were interpreted by Misawa theory.