We describe a setup for the x-ray detection of ferromagnetic resonance in the longitudinal geometry using element-specific transmission measurements. Thin magnetic film samples are placed in a static magnetic field collinear with the propagation direction of a polarized soft x-ray beam and driven to ferromagnetic resonance by a continuous wave microwave magnetic field perpendicular to it. The transmitted photon flux is measured both as a function of the x-ray photon energy and as a function of the applied static magnetic field. We report experiments performed on a 15 nm film of doped Permalloy (Ni73Fe18Gd7Co2) at the L3/L2-edges of Fe, Co, and Ni. The achieved ferromagnetic resonance sensitivity is about 0.1 monolayers/math. The obtained results are interpreted in the framework of a conductivity tensor based formalism. The factors limiting the sensitivity as well as different approaches for the x-ray detection of ferromagnetic resonance are discussed.
Majed Chergui, Camila Bacellar Cases Da Silveira, Rebecca Ann Ingle, Luca Longetti, Thomas Roland Barillot, Daniel Hollas, Ludmila Maria Diniz Leroy
Sandor Kasas, María Inés Villalba
Marcos Rubinstein, Antonio Sunjerga, Farhad Rachidi-Haeri, Thomas Chaumont