Magnetic Susceptibility Observation of Thickness Driven Spin Reorientation in Ultrathin Fe/Ni(111)/W(110) Films

Abstract

Measurements of SMOKE ac magnetic susceptibility of Fe/Ni(111)/W(110) ultrathin films were used to investigate the thickness driven spin reorientation transition. χ_⊥ exhibits a broad peak with an exponential decay at high coverage, which is in agreement with the stripe domain model studied in the temperature driven spin reorientation. A strong χ_([001]) peak, which comes from the perpendicular-canted state transition, suggests a continuous reorientation process. χ_([001]) was measured at T=255K, 300K, 315K, 330K, 360K and 380K. A temperature-thickness phase diagram was constructed and reveals the temperature dependence of the surface anisotropy. The χ_([001]) peak magnitude is attenuated by high temperature and vanishes at T=380K. It suggests a "domain melting" in the perpendicular magnetization state. Another χ_⊥ peak at t≈1.0ML correlates to the film formation. A quantitative model is built to explain the microscopic mechanism behind this peak.