Selectively thermalized sputtering for the direct synthesis of Sm–Co and Sm–Fe ferromagnetic phases

Abstract

Ferromagnetic films of the Sm–Co and Sm–Fe systems have been synthesized by sputtering onto substrates at temperatures above 600 °C so that the deposit is directly crystallized upon deposition. For the directly synthesized phases, high sputtering gas pressures were used so that the sputtered atoms transferred excess momentum to the sputtering gas atoms before arriving at the substrate. The object has been to promote the growth of possible metastable phases and to allow preferred orientation effects to be present in the films. Directly synthesized SmCo5 films grown by this method, showed a predominant (110) texture, for oxygen levels in the films of greater than about 6 at. %. As the oxygen incorporation level in the SmCo5 films was reduced to 1.4 at. % oxygen, only a (200) texture was observed. In Sm–Fe films with 6.5 at. % oxygen, a new metastable phase forms at the 1–5 composition. This oxygen stabilized metastable phase is not present in Sm–Fe films made with lower amounts of oxygen incorporation.