Magnetic and magnetocaloric properties of the new R3Co4+xAl12-x (R: Tb → Er) with the Gd3Ru4Al12 structure-type

The four phases order ferromagnetically below 24.0, 17.4, 11.5 and 5.0 K for R = Tb, Dy, Ho and Er, respectively, linearly decreasing with the de Gennes factor of the rare earth. The magnetocaloric properties have been estimated for R = Ho and Er by measuring the magnetization isotherms at various temperatures. The magnetic entropy changes reach maximum values of −12 and −10 J kg−1 K−1 for a magnetic field change from 5 to 0 T.