Spin mixing conductance at a well-controlled platinum/yttrium iron garnet interface

Qiu, Zhiyong; Ando, Keisuke; Uchida, K.; Kajiwara, Y.; Takahashi, Ryo; Nakayama, Hiroyasu; An, Toshu; Fujikawa, Y.; Saitoh, Eiji

doi:10.1063/1.4819460

Cited by 134 publications

(123 citation statements)

References 30 publications

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“…One could take advantage of the spin-mixing conductance concept [5,6] at nonmagnetic metal (NM)/ferromagnetic insulator (FMI) interfaces, which governs the interaction between the spin currents present at the NM and the magnetization of the FMI. This concept is the basis of new spindependent phenomena, including spin pumping [6][7][8][9][10][11][12], spin Seebeck effect [6,13], and spin Hall magnetoresistance (SMR) [6,[14][15][16][17][18]. In these cases, a NM with large spin-orbit coupling is required to convert the involved spin currents into charge currents via the inverse spin Hall effect [19].…”

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confidence: 99%

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Modulation of pure spin currents with a ferromagnetic insulator

et al. 2015

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We propose and demonstrate spin manipulation by magnetically controlled modulation of pure spin currents in cobalt/copper lateral spin valves, fabricated on top of the magnetic insulator Y 3 Fe 5 O 12 (YIG). The direction of the YIG magnetization can be controlled by a small magnetic field. We observe a clear modulation of the nonlocal resistance as a function of the orientation of the YIG magnetization with respect to the polarization of the spin current. Such a modulation can only be explained by assuming a finite spin-mixing conductance at the Cu/YIG interface, as it follows from the solution of the spin-diffusion equation Spintronics is a rapidly growing field that aims at using and manipulating not only the charge, but also the spin of the electron, which could lead to faster data processing, nonvolatility, and lower electrical power consumption as compared to conventional electronics [1]. Sophisticated applications such as hard-disk read heads and magnetic random access memory (MRAM) have been introduced in the last two decades.Further progress could be achieved with pure spin currents, which are an essential ingredient in an envisioned spin-only circuit that would integrate logics and memory [2]. The most basic unit in such a concept is the spin analog to the transistor, in which the manipulation of pure spin currents is crucial. The original proposal by Datta and Das [3], which is also applicable to pure spin currents [4], suggested a spin manipulation that would arise from the spin precession due to the spin-orbit interaction modulated by an electric field (Rashba coupling). However, a fundamental limitation appears here, because the best materials for spin transport are those showing the lowest spin-orbit interaction and, therefore, there has been no success in electrically manipulating the spins and propagating them at the same environment, with few exceptions [4].Alternative ways to control pure spin currents are thus desirable. One could take advantage of the spin-mixing conductance concept [5,6] at nonmagnetic metal (NM)/ferromagnetic insulator (FMI) interfaces, which governs the interaction between the spin currents present at the NM and the magnetization of the FMI. This concept is the basis of new spindependent phenomena, including spin pumping [6][7][8][9][10][11][12], spin Seebeck effect [6,13], and spin Hall magnetoresistance (SMR) [6,[14][15][16][17][18]. In these cases, a NM with large spin-orbit coupling is required to convert the involved spin currents into charge currents via the inverse spin Hall effect [19].In this Rapid Communication, we demonstrate an alternative way of modulating pure spin currents based on a magnetic, instead of electric, gating. To that end, we use lateral spin valves (LSVs). These devices allow an electrical injection and detection of pure spin currents in a NM channel by using * f.casanova@nanogune.eu ferromagnetic (FM) electrodes in a nonlocal configuration [20][21][22][23][24][25][26][27][28][29]. The LSVs have been fabricated on top of a FMI, in order to enab...

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confidence: 99%

“…Such effects are unlikely in Cu/YIG. It is worth noting that the G r of a NM/YIG interface, for a NM with a negligible spin-orbit coupling, was not experimentally measured before due to the need of the inverse spin Hall effect (and thus a high spin-orbit coupling metal) in the experiments made so far [6][7][8][9][10][11][12][13][14][15][16].…”

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confidence: 99%

Modulation of pure spin currents with a ferromagnetic insulator

et al. 2015

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“…In the case of a Pt film on the surface of a polished single-crystalline YIG slab (Pt/YIG) [ Fig. 1(c)] [30], anomalous features in magnetic field dependence of the SSE voltages at low temperatures are attributed to the magnon-phonon interaction at the "touching" points between the magnon and transverse acoustic (TA) and longitudinal acoustic (LA) phonon as magnon dispersion curve is lifted by the applied field while phonon is not affected by the field [ Fig. 1(d)] [31].…”

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confidence: 99%

Direct observation of magnon-phonon coupling in yttrium iron garnet

Man

Shi

et al. 2017

Phys. Rev. B

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The magnetic insulator yttrium iron garnet (YIG) with a ferrimagnetic transition temperature of ∼560 K has been widely used in microwave and spintronic devices. Anomalous features in the spin Seeback effect (SSE) voltages have been observed in Pt/YIG and attributed to the magnon-phonon coupling. Here we use inelastic neutron scattering to map out low-energy spin waves and acoustic phonons of YIG at 100 K as a function of increasing magnetic field. By comparing the zero and 9.1 T data, we find that instead of splitting and opening up gaps at the spin wave and acoustic phonon dispersion intersecting points, magnon-phonon coupling in YIG enhances the hybridized scattering intensity. These results are different from expectations of conventional spin-lattice coupling, calling for new paradigms to understand the scattering process of magnon-phonon interactions and the resulting magnon-polarons.Spin waves (magnons) and phonons are propagating disturbance of the ordered magnetic moment and lattice vibrations, respectively. They constitute two fundamental quasiparticles in a solid and can couple together to form a hybrid quasiparticle [1,2]. Since our current understandings of these quasiparticles are based on linearized models that ignore all the high-order terms than quadratic terms and neglect interactions among the quasiparticle themselves [3], magnons and phonons are believed to be stable and unlikely to interact and breakdown for most purposes [4]. Therefore, discovering and understanding how the otherwise stable magnons and phonons can couple and interact with each other to influence the electronic properties of solids are one of the central themes in modern condensed matter physics.In general, spin-lattice (magnon-phonon) coupling can modify magnon in two different ways. First, the static lattice distortion induced by the magnetic order may affect the anisotropy of magnon exchange couplings, as seen in the spin waves of iron pnictides with large inplane magnetic exchange anisotropy [5]. Second, the dynamic lattice vibrations interact with time-dependent spin waves may give rise to significant magnon-phonon coupling [6,7]. One possible consequence of such coupling is to create energy gaps in the magnon dispersion at the nominal intersections of the magnon and phonon modes [8,9], as seen in antiferromagnet (Y,Lu)MnO 3 [10]. Alternatively, magnon-phonon coupling may give rise to spin-wave broadening at the magnon-phonon crossing points [11]. In both cases, we expect the integrated intensity of hybridized excitations at the intersecting points to be the sum of separate magnon and phonon scattering intensity without spin-lattice coupling [8]. Finally, if magnon and phonon lifetime-broadening is smaller than their interaction strength, the resulting mixed quasiparticles can form magnon polarons [6,7].Here we use inelastic neutron scattering to study lowenergy ferromagnetic magnons and acoustic phonons in the ferrimagnetic insulator yttrium iron garnet (YIG) with chemical formula -14]. At zero field and 100 K, we confir...

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“…Another key feature of magnon spintronics is its close relationship to a multitude of physical phenomena like spin-pumping, spin-transfer torque, spin Seebeck effect, and (inverse) spin Hall effect, which allow for the amplification, generation and transformation between charge currents and magnonic currents [7][8][9][10][11][12][15][16][17][18][19][20][21][22][23][24] . Hetero-structures of YIG covered with a thin layer of platinum (Pt) have proven to show these effects which opens a way to a new class of insulator based spintronics.…”

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confidence: 99%

Spin-wave excitation and propagation in microstructured waveguides of yttrium iron garnet/Pt bilayers

Pirro

Brächer

Chumak

et al. 2014

Applied Physics Letters

157

119

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We present an experimental study of spin-wave excitation and propagation in microstructured waveguides patterned from a 100 nm thick yttrium iron garnet (YIG)/platinum (Pt) bilayer. The life time of the spin waves is found to be more than an order of magnitude higher than in comparably sized metallic structures despite the fact that the Pt capping enhances the Gilbert damping. Utilizing microfocus Brillouin light scattering spectroscopy, we reveal the spin-wave mode structure for different excitation frequencies. An exponential spin-wave amplitude decay length of 31 µm is observed which is a significant step towards low damping, insulator based micro-magnonics.

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Spin mixing conductance at a well-controlled platinum/yttrium iron garnet interface

Cited by 134 publications

References 30 publications

Modulation of pure spin currents with a ferromagnetic insulator

Modulation of pure spin currents with a ferromagnetic insulator

Direct observation of magnon-phonon coupling in yttrium iron garnet

Spin-wave excitation and propagation in microstructured waveguides of yttrium iron garnet/Pt bilayers

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