First-order magnetization process in Nd2(Fe1-xAlx)17 single crystals

High field magnetization measurements have been performed for single crystals of Nd2(Fe1-xAlx)17. In the sample with x=0.04, the easy direction is not within the c-plane at 4.2 K but in the plane spanned by the b-and c-axes. When the field is applied along the c-axis at 4.2 K, abrupt increases in magnetization have been observed successively at 115 and 150 kOe. These results have been well reproduced by a simple model calculation on the basis of the crystalline electric field theory. ((orig.))