Analysis of the line shape of electrically detected ferromagnetic resonance

Harder, Michael; Cao, Zhong; Gui, Y. S.; Fan, Xiaolong; Hu, C.‐M.

doi:10.1103/physrevb.84.054423

Cited by 205 publications

(208 citation statements)

References 58 publications

(166 reference statements)

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“…Our analysis of the current-induced torques using equation (1) is not necessarily valid if the torques do not act in phase with the microwave current. In comparison with electrically detected FMR measurements where the ARTICLE microwave current is capacitively or inductively coupled into the sample 35 , we do not expect a phase-shift between the microwave current and induced fields as the current is conducted ohmically. Nevertheless, we might worry that some part of our microwave resonator circuit leads to a phase shift.…”

Section: Resultsmentioning

confidence: 99%

Complementary spin-Hall and inverse spin-galvanic effect torques in a ferromagnet/semiconductor bilayer

et al. 2015

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Recently discovered relativistic spin torques induced by a lateral current at a ferromagnet/ paramagnet interface are a candidate spintronic technology for a new generation of electrically controlled magnetic memory devices. The focus of our work is to experimentally disentangle the perceived two model physical mechanisms of the relativistic spin torques, one driven by the spin-Hall effect and the other one by the inverse spin-galvanic effect. Here, we show a vector analysis of the torques in a prepared epitaxial transition-metal ferromagnet/ semiconductor-paramagnet single-crystal structure by means of the all-electrical ferromagnetic resonance technique. By choice of our structure in which the semiconductor paramagnet has a Dresselhaus crystal inversion asymmetry, the system is favourable for separating the torques due to the inverse spin-galvanic effect and spin-Hall effect mechanisms into the field-like and antidamping-like components, respectively. Since they contribute to distinct symmetry torque components, the two microscopic mechanisms do not compete but complement each other in our system.

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Section: Resultsmentioning

confidence: 99%

Complementary spin-Hall and inverse spin-galvanic effect torques in a ferromagnet/semiconductor bilayer

et al. 2015

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“…Therefore we measure the planar Hall effect (PHE) and the anomalous Hall effect (AHE) in CoFeB. It was proposed and shown by Azevedo et al 28 and Harder et al 31 that the resulting voltage is well described by both a symmetric and an asymmetric contributions. In the CoFeB reference film, the asymmetric component is dominant.…”

Section: B Electromotive Force Measured On the Reference Samplementioning

confidence: 99%

“…28,31 The symmetric and asymmetric contributions as well as the offset voltage are proportional to the microwave power. It means that V of f set , V sAM R , and V asAM R are proportional to h 2 rf , where h rf is the microwave magnetic field strength.…”

Section: B Electromotive Force Measured On the Reference Samplementioning

confidence: 99%

Spin pumping and inverse spin Hall effect in germanium

et al. 2013

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We have measured the inverse spin Hall effect (ISHE) in n-Ge at room temperature. The spin current in germanium was generated by spin pumping from a CoFeB/MgO magnetic tunnel junction in order to prevent the impedance mismatch issue. A clear electromotive force was measured in Ge at the ferromagnetic resonance of CoFeB. The same study was then carried out on several test samples, in particular we have investigated the influence of the MgO tunnel barrier and sample annealing on the ISHE signal. First, the reference CoFeB/MgO bilayer grown on SiO 2 exhibits a clear electromotive force due to anisotropic magnetoresistance and anomalous Hall effect which is dominated by an asymmetric contribution with respect to the resonance field. We also found that the MgO tunnel barrier is essential to observe ISHE in Ge and that sample annealing systematically lead to an increase of the signal. We propose a theoretical model based on the presence of localized states at the interface between the MgO tunnel barrier and Ge to account for these observations. Finally, all of our results are fully consistent with the observation of ISHE in heavily doped n-Ge and we could estimate the spin Hall angle at room temperature to be ≈0.001.

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“…These effects have often been neglected in the quantitative analyses on the observed d.c. voltage generated in a non-magnetic layer next to a ferromagnetic layer under FMR; the non-negligible contribution of these effects was pointed out only recently 22,23,27 . It is known that a ferromagnetic (Ga,Mn)As, which can be grown seamlessly on GaAs 28 , shows sizable galvanomagnetic effects 29,30 , and thus we expect that (Ga,Mn)As/p-GaAs bilayer structure is a suitable system to investigate the d.c. voltage observed under FMR.…”

mentioning

confidence: 99%

Direct-current voltages in (Ga,Mn)As structures induced by ferromagnetic resonance

2013

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Spin pumping is the phenomenon that magnetization precession in a ferromagnetic layer under ferromagnetic resonance produces a pure spin current in an adjacent non-magnetic layer. The pure spin current is converted to a charge current by the spin-orbit interaction, and produces a d.c. voltage in the non-magnetic layer, which is called the inverse spin Hall effect. The combination of spin pumping and inverse spin Hall effect has been utilized to determine the spin Hall angle of the non-magnetic layer in various ferromagnetic/non-magnetic systems. Magnetization dynamics of ferromagnetic resonance also produces d.c. voltage in the ferromagnetic layer through galvanomagnetic effects. Here we show a method to separate voltages of different origins using (Ga,Mn)As/p-GaAs as a model system, where sizable galvanomagnetic effects are present. Neglecting the galvanomagnetic effects can lead to an overestimate of the spin Hall angle by factor of 8, indicating that separating the d.c. voltages of different origins is critical.

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Analysis of the line shape of electrically detected ferromagnetic resonance

Cited by 205 publications

References 58 publications

Complementary spin-Hall and inverse spin-galvanic effect torques in a ferromagnet/semiconductor bilayer

Complementary spin-Hall and inverse spin-galvanic effect torques in a ferromagnet/semiconductor bilayer

Spin pumping and inverse spin Hall effect in germanium

Direct-current voltages in (Ga,Mn)As structures induced by ferromagnetic resonance

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