Layer resolved magnetization dynamics in interlayer exchange coupled Ni81Fe19∕Ru∕Co90Fe10 by time resolved x-ray magnetic circular dichroism

Abstract

The magnetization dynamics of each layer of interlayer exchange coupled Ni 81 Fe 19 / Ru͑t͒ / Co 90 Fe 10 films was investigated by time resolved x-ray magnetic circular dichroism ͑TR-XMCD͒ after pulsed excitation. The coupling was changed from ferromagnetic to antiferromagnetic by variation of the Ru thickness t. The precessional motion of the individual layers was detected separately by measuring the XMCD signal at the L 3 absorption edge of either nickel or cobalt. From the observation of two frequency components in the precession of both layers in samples with negligible interlayer exchange coupling, the presence of a different coupling mechanism was concluded. Using two different sample geometries, the influence of antiphase and in-phase excitation on the triggered dynamics was studied.

Longitudinal detection of ferromagnetic resonance using x-ray transmission measurements

“…These experiments allowed element-specific studies of the magnetization precession in ferromagnetic 2,8,9 and ferrimagnetic 3,10,11,13,16 compounds as well as measurements of the relative phase and precession angle of the magnetization in coupled metal layers. 6,8,9,14,15,17 XFMR experiments have revealed, e.g., the precession of induced magnetic moments of nonmagnetic species such as Y and O in the ferrimagnetic oxide Y 3 Fe 5 O 12 . 11,16 Further, it has been pointed out that XFMR may potentially be used to quantitatively determine dynamic changes of the spin and orbital magnetization using the x-ray magnetic circular dichroism ͑XMCD͒ sum rules.…”

“…10͔͒, using either fluorescence, [2][3][4]8,10,11,13,16 reflectivity, 2,8 or transmission measurements. 1,5,6,8,9,12,14,15,17 Ferromagnetic resonance signals have been observed at energies from 500 eV to 7 keV on the following atoms: Fe ͑L 3 / L 2 -edges and K-edge͒, Ni ͑L 3 / L 2 -edges͒, Co ͑L 3 / L 2 -edges͒, Gd ͑M 4 / M 5 -edges͒, Y ͑L 3 / L 2 -edges͒, O ͑K-edge͒, and Tb ͑M 5 -edge͒. These experiments allowed element-specific studies of the magnetization precession in ferromagnetic 2,8,9 and ferrimagnetic 3,10,11,13,16 compounds as well as measurements of the relative phase and precession angle of the magnetization in coupled metal layers.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Element sensitivity is obtained by choosing the x-ray photon energy corresponding to a core-to-valence band transition of the atom under investigation. The relatively large separation between the absorption lines of the different elements at the x-ray energies of interest as well as the x-ray absorption line shape dependence on the type and position of neighbor atoms allows one to study the magnetic properties of each element separately in well defined environments.…”

A compact apparatus for studies of element and phase-resolved ferromagnetic resonance

“…The time-resolved approach has been extended by our group [12,13,14,15,16]and other researchers [17] to examine GHz-range FMR with elemental-specificity. An advantage of time-resolved techniques is that the phase information between the cw excitation and the precessing magnetic moments in the sample is preserved, permitting a flexible exploration of the multi-dimensional phase space (excitation frequency, phase of the response, photon energy, and applied field) inherent in the experiment.…”

Precessional damping of Fe magnetic moments in a FeNi film

“…In addition to FMR-based techniques, pump-probe setups were realized in recent years. Time-resolved XMCD experiments in reflection or transmission geometry [10,11] provide additional information about the constituting elements while using magnetic field pulse excitation. Each of the element-resolved experimental techniques has specific advantages and disadvantages, which have been described in some detail by Guan et al [12].…”