Ferromagnetic resonance of ultrathin metallic layers

TLDR

FMR has advanced understanding of magnetic behavior in ultrathin single films. The study examines how magnetic anisotropy energy (MAE) quantitatively describes temperature‑ and thickness‑dependent magnetization reorientation transitions in Ni/Cu(001) and Gd/W(110). The authors employ in‑situ FMR under ultrahigh vacuum to measure temperature‑dependent magnetization, relaxation rates near the Curie point, and second‑ and fourth‑order MAE constants in magnetic monolayers. They find that MAE governs temperature‑ and thickness‑dependent reorientation transitions and report initial g‑factor anisotropy results linked to orbital moment anisotropy.

Abstract

The contribution that the technique of ferromagnetic resonance (FMR) has made to the understanding of the magnetic behaviour of ultrathin single films is reviewed. Experimental methods to measure FMR in situ in ultrahigh vacuum are presented. The temperature dependence of the magnetization, of the magnetic relaxation rate in the vicinity of the Curie temperature, and of the second- and fourth-order magnetic anisotropy energy (MAE) constants can be measured by FMR in situ for magnetic monolayers. Using the cases of Ni/Cu(001) and Gd/W(110) as examples, the role of the MAE for the quantitative description of temperature- and thickness-dependent reorientation transitions of the magnetization is discussed. Initial results for the anisotropy of the g-factor which is related to the anisotropy of the orbital moment (and the MAE) are presented.