ANOMALOUS THERMAL-EXPANSION OF MONOCRYSTALLINE YCO4B

Thermal expansion of monocrystalline YCo4B along the principal axes, m easured by a capacitance method, shows step-like changes at the spin r eorientation transition. From these step-like changes, values of the a nisotropic magnetostriction constants at the transition temperature ha ve been derived as: lambda(1)(alpha.2) = -0.7 x 10(-4) and lambda(2)(a lpha.2) = 1.4 x 10(-4). These values are an order of magnitude smaller than those reported for some RCo5 compounds where R is a magnetic rar e earth. Their presence might be connected to unquenched orbital momen ts of Co in YCo4B. (C) 1998 Elsevier Science B.V. All rights reserved.