Magnetic phase diagram of La(FexAl1-x)13 in the vicinity of the ferromagnetic-antiferromagnetic phase boundary

The magnetic properties in the vicinity of the ferromagnetic (F)-antiferromagnetic (AF) phase boundary have been investigated over a wide temperature range for La(FexAl1-x)(13) (0.861 less than or equal to x less than or equal to 0.869). The temperature induced magnetic phase transition from F to AF has been observed in the concentration range 0.861 less than or equal to x less than or equal to 0.864 to be accompanied by a discontinuous volume change of about 0.14%. In the AF state, the first-order phase transition to the F state is induced by applying a magnetic field and the transition becomes of second-order above a certain temperature. The magnetic phase diagrams could be explained by taking into consideration a change in the temperature dependence of the staggered susceptibility relative to the uniform susceptibility with increasing Fe concentration. (C) 2000 Elsevier Science S.A. All rights reserved.