Structure of Sm–Co/Fe–Co multilayer films with in-plane magnetic anisotropies prepared on MgO(110) single-crystal substrates

• Sm–Co/Fe–Co multilayer films are prepared on MgO(110) substrates by UHV–MBE.
• The film growth behavior is investigated by in-situ RHEED.
• Multilayer films involving Sm–Co(1–100) crystal show uniaxial magnetic anisotropies.

Sm17Co83/Fe65Co35 (at. %) multilayer films are prepared on MgO(110) substrates at 500 °C by ultra-high vacuum molecular beam epitaxy. The film crystallographic properties during formation are investigated by in-situ reflection high-energy electron diffraction. The 1st Fe–Co layer epitaxially grows on the substrate with two variants whose orientations are rotated around the film normal by 180° each other. The 1st Sm–Co layer formed on the 1st Fe–Co layer involves a small volume of amorphous phase in addition to epitaxial (11¯00)) crystal of RT5 structure with the c-axis lying in the film plane. The crystallographic quality of 2nd Fe–Co layer is inferior to that of 1st Fe–Co layer. The 2nd Sm–Co layer is composed of polycrystal and amorphous phases. The crystallographic properties of Sm–Co and Fe–Co layers are delicately influenced by those of lower layers. The Sm–Co/Fe–Co multilayer films involving Sm–Co(11¯00)RT5 epitaxial crystal show in-plane uniaxial magnetic anisotropies reflecting the magnetocrystalline anisotropy of SmCo5 crystal. The coercivity increases with increasing the volume of Sm–Co(11¯00)RT5 crystal.