On the magnetic properties of pseudo-Laves phases RE1-yYyNi4-xAlxMg with RE = La, Ce and Gd prepared by both melting and ball milling

International audienceMagneticproperties of RE1−yYyNi4−xAlxMg (RE = La, Ce and Gd) are reported. LaNi4Mg displays a weak magnetization indicating that Ni is non magnetic as often observed in RENi2 compounds. The magnetization of CeNi4Mg compounds shows a Curie Weiss behaviour with an effective paramagnetic moment μeff = 2.2 μB. The magnetization of Gd compounds is dominated by the contribution of Gd moment with a paramagnetic effective moment close to 7.7 μB/Gd for all studied compounds. The Curie temperature, which is 75 K for GdNi2, decreases almost linearly with the number of Gd neighbours when more than half Gd is replaced by Y. The decrease of crystallinity of GdNi4Mg, which is monitored by ball milling and heat treatment, strongly influences the magneticproperties and a relationship between the transition temperature and the crystallites size is reported