Enhanced magnetocaloric response in Cr/Mo containing Nanoperm-type amorphous alloys

The magnetocaloric effect of Fe76Cr8-xMoxCu1B15 (x=0,4) alloys is studied. Although the combined addition of Cr and Mo is more efficient in tuning the Curie temperature of the alloy, the Mo-free alloy presents a higher magnetocaloric response. The refrigerant capacity (RC) for the Mo-containing alloy is comparable to that of Gd5Ge1.9Si2Fe0.1 (for a field of 50 kOe, RC=273 J kg(-1) for the Mo alloy vs 240 J kg(-1) for the Gd-based one), with a larger temperature span of the optimal refrigeration cycle (250 K vs 90 K, respectively). The restriction of the temperature span to 90 K gives RC=187 J kg(-1) for the Mo alloy. A master curve behavior for the magnetic entropy change is also evidenced.