We demonstrate a layer-and time-resolved measurement of ferromagnetic resonance (FMR) in a Ni 81 Fe 19 / Cu / Co 93 Zr 7 trilayer structure. Time-resolved x-ray magnetic circular dichroism has been developed in transmission, with resonant field excitation at a FMR frequency of 2.3 GHz. Small-angle (to 0.2°) , time-domain magnetization precession could be observed directly, and resolved to individual layers through elemental contrast at Ni, Fe, and Co edges. The phase sensitivity allowed direct measurement of relative phase lags in the precession oscillations of individual elements and layers. A weak ferromagnetic coupling, difficult to ascertain in conventional FMR measurements, is revealed in the phase and amplitude response of individual layers across resonance. -2 --
We present a compact sample holder equipped with electromagnets and high frequency transmission lines; the sample holder is intended for combined x-ray magnetic circular dichroism (XMCD) and ferromagnetic resonance measurements (FMR). Time-resolved measurements of resonant x-ray detected FMR during forced precession are enabled by use of a rf excitation that is phase-locked to the storage ring bunch clock. Several applications of the combined XMCD + FMR technique are presented, demonstrating the flexibility of the experimental design.
We present measurements of element-and time-resolved ferromagnetic resonance ͑FMR͒ in magnetic thin films at gigahertz frequencies via an implementation of time-resolved x-ray magnetic circular dichroism ͑TR-XMCD͒. By combining TR-XMCD and FMR, using a rf excitation that is phase locked to the photon bunch clock, the dynamic response of individual layers or precession of individual elements in an alloy can be measured. The technique also provides extremely accurate measurements of the precession cone angle ͑to 0.1°͒ and the phase of oscillation ͑to 2°, or ϳ5 ps at 2.3 GHz͒. TR-XMCD combined with FMR can be used to study the origins of precessional damping by measuring the relative phase of dissimilar precessing magnetic moments. We have used the technique to measure the response of specific elements and separate layers in several alloys and structures, including a single Ni 81 Fe 19 layer, a pseudo-spin-valve structure ͑Ni 81 Fe 19 /Cu/Co 93 Zr 7 ͒, magnetic bilayers consisting of low damping ͑Co 93 Zr 7 ͒ and high damping ͑Tb-doped Ni 81 Fe 19 ͒ layers joined across a common interface, and elemental moments in Tb-doped Ni 81 Fe 19 .
We present experimental techniques to measure magnetization precession of individual layers in a "spin-valve" trilayer. Precessional motions of individual Ni 81 Fe 19 and Co 93 Zr 7 layers have been separated in Ni 81 Fe 19 /Cu/Co 93 Zr 7 using ±45 ps time-resolved x-ray magnetic circular dichroism ͑tr-XMCD͒ at Fe and Co edges. We compare the efficacy of two experimental configurations in this paper. Pulsed-field tr-XMCD measurements in reflectivity are compared with resonant-field tr-XMCD measurements in transmission. Despite the order of magnitude larger angles of precession excited in pulsed-field reflectivity measurements, data quality is found to be superior in resonant-field transmission measurements. Relative roles of sample preparation and timing jitter in the different techniques are discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.