Magnetic and structural instabilities of ferromagnetic and antiferromagnetic Fe/Cu(100)

摘要

Fe wedges epitaxially grown on Cu(100) have been employed to investigate the interplay between magnetic and structural instabilities. 2--4 ML clean Fe films grown at room temperature are ferromagnetic with perpendicular easy axes. Bcc Fe films > 11ML thick are ferromagnetic with in-plane easy axes. Most importantly, 6--11ML fcc Fe films are antiferromagnetic and have a ferromagnetic surface. Films grown below 200K and annealed to room temperature do not exhibit the antiferromagnetic phase, but remain ferromagnetic and undergo a spin-reorientation transition from perpendicular to in-plane at (approximately)6ML. A new phase diagram for Fe/Cu(100) is proposed as a function of thickness and growth temperature. In addition, an impurity-stabilized layer-by-layer growth that persists to 30--40 monolayers (ML) Fe is also reported.