Effects of Ar pressure on magnetic and magnetocaloric properties of sputtered Er–Co thin films

The magnetic and magnetocaloric properties of Er–Co thin films fabricated by sputtering under an Ar pressure (PAr) varying from 2 to 10 mTorr in steps of 2 mTorr are investigated. The content of Co in the sputtered thin films decreases slightly as the PAr increases from 2 to 10 mTorr, resulting in a film composition varying from ErCo1.07 to ErCo0.93. Extensive changes in the magnetic and magnetocaloric properties are observed. As the PAr increases, the compensation temperature increases substantially from 83 to 141 K, as well as the temperature at which the maximum change in the magnetic entropy occurs, particularly in the low PAr range. Considering the small change observed in the composition of the thin films as a function of PAr, the changes in the magnetic and magnetocaloric properties are extensive, indicating that the PAr plays an important role in affecting the aforementioned properties in amorphous magnetic thin films.