Preparation, crystal structure, magnetic and magnetothermal properties of (GdxR5-x)Si4, where R=Pr and Tb, alloys

The series of alloys (GdxTb5-x)Si-4 (x=0,2.5,3,3.5,4,4.5,5) and (GdxPr5-x)Si-4 (x=4,4.25,4.5) have been prepared. Their room temperature crystal structure has been established, and dc magnetization and ac magnetic susceptibility have been measured in the temperature range from 4.2 to 550 K and in dc magnetic fields up to 50 kOe. The magnetocaloric effect has been calculated from the magnetization data and, for one of the alloys, from the heat capacity data. The magnetocaloric effect values from the two different measurements are in excellent agreement. The (GdxTb5-x)Si-4 alloys exhibit magnetocaloric effects in low magnetic fields (<20 kOe) comparable to that of Gd metal and, therefore, they represent a new class of promising magnetic refrigerant materials. (C) 2001 American Institute of Physics.