Spin pumping through a topological insulator probed by x-ray detected ferromagnetic resonance

Figueroa, A. I.; Baker, Alexander A.; Collins-McIntyre, L. J.; Hesjedal, T.; Laan, G. van der

doi:10.1016/j.jmmm.2015.07.013

Cited by 22 publications

(18 citation statements)

References 50 publications

(56 reference statements)

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“…For full details of the x-ray detected FMR (XFMR) methodology, we refer the reader to Ref. [27]. All XFMR measurements were performed at the Ni and Co L 3 edges.…”

mentioning

confidence: 99%

“…A driving frequency of 4 GHz was used to excite precession across the NiFe resonance at ∼14 mT, while the XMCD amplitudes at the Co and Ni L 3 edges were measured. The relative phase of microwave excitation and x-ray pulse was varied, extracting amplitude and phase of precession from plots of time-dependent magnetization [9,27]. The results are plotted in Fig.…”

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confidence: 99%

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Anisotropic Absorption of Pure Spin Currents

et al. 2016

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Spin transfer in magnetic multilayers offers the possibility of ultrafast, low-power device operation. We report a study of spin pumping in spin valves, demonstrating that a strong anisotropy of spin pumping from the source layer can be induced by an angular dependence of the total Gilbert damping parameter, α, in the spin sink layer. Using lab- and synchrotron-based ferromagnetic resonance, we show that an in-plane variation of damping in a crystalline Co_{50}Fe_{50} layer leads to an anisotropic α in a polycrystalline Ni_{81}Fe_{19} layer. This anisotropy is suppressed above the spin diffusion length in Cr, which is found to be 8 nm, and is independent of static exchange coupling in the spin valve. These results offer a valuable insight into the transmission and absorption of spin currents, and a mechanism by which enhanced spin torques and angular control may be realized for next-generation spintronic devices.

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“…For full details of the x-ray detected FMR (XFMR) methodology, we refer the reader to Ref. [27]. All XFMR measurements were performed at the Ni and Co L 3 edges.…”

mentioning

confidence: 99%

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confidence: 99%

Anisotropic Absorption of Pure Spin Currents

et al. 2016

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“…XFMR offers element-and thus layer-specific measurement of the precessional dynamics of each FM layer on a picosecond timescale 21, [52][53][54][55] . In this technique, the magnetization of the sample in a magnetic field is pumped by a radio-frequency (RF) field to generate a precessing moment (i.e., FMR), which is probed using the XMCD effect 56,57 .…”

Section: Xfmrmentioning

confidence: 99%

“…A schematics of our XFMR setup can be found in Ref. 52. The incident x-rays impinge the sample through a hole in the signal line of the CPW.…”

Section: Xfmrmentioning

confidence: 99%

“…The x-ray beam has an incidence angle of 35 • with respect to the plane of the sample, to ensure that the XMCD is sensitive to the larger in-plane component of the magnetization precession. The x-ray absorption was measured in transmission geometry by detecting the x-ray excited optical luminescence emerging from the MgO substrate, using a photodiode mounted behind the sample 52 .…”

Section: Xfmrmentioning

confidence: 99%

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Antidamping torques from simultaneous resonances in ferromagnet-topological insulator-ferromagnet heterostructures

Baker

Figueroa

Hesjedal

et al. 2019

Journal of Magnetism and Magnetic Materials

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We studied the magnetodynamics of ferromagnetic films coupling across a topological insulator (TI) Bi2Se3 layer using ferromagnetic resonance (FMR). TIs have attracted much attention across the physics community as they hold the potential for dissipationless carrier transport, extremely high spin-orbit torques, and are host to novel quantum effects. To investigate the coupling between the ferromagnetic (FM) layers, vector network analyzer (VNA)-FMR measurements of the resonance linewidth were performed as a function of bias field angle. By bringing the resonances of the two FM layers into close proximity, it was possible to observe antidamping torques that lead to a narrowing of linewidth, a characteristic of spin pumping. The element-and hence layer-specific technique of x-ray detected ferromagnetic resonance (XFMR) was used to circumvent the difficulty of obtaining accurate fits to the two overlapping resonances in close proximity. Our results confirm that the interaction across the TI is a dynamic exchange mediated by spin pumping, as opposed to a selfcoupling of the surface state or similar, more unconventional mechanisms.

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Picosecond time-resolved X-ray ferromagnetic resonance measurements at Shanghai synchrotron radiation facility

Xia

Cao

et al. 2022

NUCL SCI TECH

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An experimental picosecond time-resolved X-ray ferromagnetic resonance (TR-XFMR) apparatus with a time resolution of 13 ps (RMS) or 31 ps (FWHM) was constructed and demonstrated in the 07U and 08U1A soft X-ray beamlines at the Shanghai Synchrotron Radiation Facility (SSRF) using pump-probe detection and X-ray magnetic circular dichroism (XMCD) spectroscopy. Element and time-resolved ferromagnetic resonance was excited by continuous microwave phase-locking of the bunch clock within the photon beam during synchrotron radiation and was characterized by detecting the magnetic circular dichroism signals of the elements of interest in the magnetic films. Using this equipment, we measured the amplitude of the element-specific moment precession during ferromagnetic resonance (FMR) at 2 GHz in a single Ni81Fe19 layer.

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Spin pumping through a topological insulator probed by x-ray detected ferromagnetic resonance

Cited by 22 publications

References 50 publications

Anisotropic Absorption of Pure Spin Currents

Anisotropic Absorption of Pure Spin Currents

Antidamping torques from simultaneous resonances in ferromagnet-topological insulator-ferromagnet heterostructures

Picosecond time-resolved X-ray ferromagnetic resonance measurements at Shanghai synchrotron radiation facility

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