MAGNETIC-PROPERTIES OF THE Y1-XGDXCO3B2 SYSTEM

Magnetic properties of Y1-xGdxCo3B2 with x = 0, 0.2, 0.4, 0.6, 0.8, and 1.0 have been studied in a wide temperature range from 4.2 to 1250 K. All compounds studied here have the CeCo3B2-type structure which is a derivative of the RCo5 type one. In this system, the Co atom is nonmagnetic down to 4.2 K and the Curie temperature decreases almost linearly with increasing composition x and is expected to vanish at around x = 0 (YCo3B2). For the sample with x = 0.2, a spin-glass freezing point has been found in addition to the usual ferromagnetic Curie temperature. Gd magnetic moments obtained from the saturation magnetizations at T = 4.2 K are generally smaller than those obtained from the Curie-Weiss constants in the high-temperature paramagnetic region, which suggests a slight polarization of the Co atoms antiparallel to the Gd moment in the ferromagnetic region.