Magnetocaloric effect in the ferromagnetic GdNi4M (MÂ =Â Al, Si) and antiferromagnetic NdNiAl4 compounds

► Magnetocaloric effect in GdNi4Al and GdNi4Si slightly better than in GdNi5. ► Phase transition in GdNi4Al and GdNi4Si may be of the first order. ► Anomalous (sign change) magnetocaloric effect in antiferromagnetic NdNiAl4. ► Neutron diffraction: the magnetic order in NdNiAl4 is not of a simple AFM type.