Spin pumping into superconductors: A new probe of spin dynamics in a superconducting thin film

Inoue, Masashi; Ichioka, Masanori; Adachi, Hiroto

doi:10.1103/physrevb.96.024414

Cited by 67 publications

(113 citation statements)

References 54 publications

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“…A monotonic decay of iSH voltages in the un-patterned and stripe-patterned samples across Tc (Fig. S5) confirms the absence of the superconducting coherence effect [44][45][46] in our system (i.e. metallic/conducting FM/SC bilayers).…”

Section: Section S5 Inverse Spin-hall Voltages In the Vicinity Of Tcsupporting

confidence: 73%

Spin-Pumping-Induced Inverse Spin Hall Effect in Nb/Ni80Fe20 Bilayers and its Strong Decay Across the Superconducting Transition Temperature

et al. 2018

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We quantify the spin Hall angle θ SH and spin-diffusion length l sd of Nb from inverse spin Hall effect (ISHE) measurements in Nb/Ni 80 Fe 20 bilayers under ferromagnetic resonance. By varying the Nb thickness t Nb and comparing to a Ni 80 Fe 20 /Pt reference sample, room temperature values of θ SH and l sd for Nb are estimated to be approximately −0.001 and 30 nm, respectively. We also investigate the ISHE as a function of temperature T for different t Nb . Above the superconducting transition temperature T c of Nb, a clear t Nb -dependent T evolution of the ISHE is observed whereas below T c , the ISHE voltage drops rapidly and is below the sensitivity of our measurement setup at a lower T. This suggests the strong decay of the quasiparticle (QP) charge-imbalance relaxation length across T c , as supported by an additional investigation of the ISHE in a different sample geometry along with model calculation. Our finding suggests careful consideration should be made when developing superconductor spin Hall devices that intend to utilize QP-mediated spin-to-charge interconversion.

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Section: Section S5 Inverse Spin-hall Voltages In the Vicinity Of Tcsupporting

confidence: 73%

Spin-Pumping-Induced Inverse Spin Hall Effect in Nb/Ni80Fe20 Bilayers and its Strong Decay Across the Superconducting Transition Temperature

et al. 2018

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“…According to the theory, Gilbert damping is related to the interfacial s-d exchange interaction and the imaginary part of the dynamic spin susceptibility of the SC [20]. 2 Im ( )…”

Section: Resultsmentioning

confidence: 99%

“…After the growth, a thin Al2O3 layer (~ 10 nm) was deposited in situ as a capping layer to avoid sample degradation with air exposure. The Curie temperature of the GdN film was determined via the offset-magnetization as a function of the temperature using Gilbert damping [20]. Hence, the interfacial s-d exchange coupling provides the route to detect the spin dynamics of the NbN layer by measuring the magnetization dynamics of GdN.…”

Section: Methodsmentioning

confidence: 99%

“…GdN is an insulating FM. A 10 nm NbN film is used for the NbN (t)/GdN (d)/NbN (t) samples to justify the assumption that the spin backflow from SC is small in the theoretical study [20]. In a typical sample of NbN (10)/GdN (5)/NbN (10) (with thickness in nm), the Curie temperature (TCurie) of GdN is determined to be ~ 38 K from the temperature dependence of magnetic moments ( Fig.…”

Section: Methodsmentioning

confidence: 99%

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Probe of spin dynamics in superconducting NbN thin films via spin pumping

et al. 2018

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The emerging field of superconductor (SC) spintronics has attracted intensive attentions recently.Many fantastic spin dependent properties in SCs have been discovered, including large magnetoresistance, long spin lifetimes and the giant spin Hall effect, etc. Regarding the spin dynamics in superconducting thin films, few studies has been reported yet. Here, we report the investigation of the spin dynamics in a s-wave superconducting NbN film via spin pumping from an adjacent insulating ferromagnet GdN film. A profound coherence peak of the Gilbert damping of GdN is observed slightly below the superconducting critical temperature of the NbN, which agrees well with recent theoretical prediction for s-wave SCs in the presence of impurity spin-orbit scattering. This observation is also a manifestation of the dynamic spin injection into superconducting NbN thin film. Our results demonstrate that spin pumping could be used to probe the dynamic spin susceptibility of superconducting thin films, thus pave the way for future investigation of spin dynamics of interfacial and two dimensional crystalline SCs.

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“…In such systems charge and (non-collinear) spin transport are closely linked and need to be treated on the same footing. Recently there has also been increased interest to couple superconductors to magnets and find out how superconductivity affects the magnetization dynamics, [5][6][7][8][9][10][11][12][13][14][15] including thermally driven effects [16]. On the other hand, recent work has shown that a combination of magnetic and superconducting systems results to giant thermoelectric effects [17][18][19][20] coupling charge and heat currents.…”

mentioning

confidence: 99%

Nonlinear spin torque, pumping, and cooling in superconductor/ferromagnet systems

et al. 2020

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We study the effects of the coupling between magnetization dynamics and the electronic degrees of freedom in a heterostructure of a metallic nanomagnet with dynamic magnetization coupled with a superconductor containing a steady spin-splitting field. We predict how this system exhibits a non-linear spin torque, which can be driven either with a temperature difference or a voltage across the interface. We generalize this notion to arbitrary magnetization precession by deriving a Keldysh action for the interface, describing the coupled charge, heat and spin transport in the presence of a precessing magnetization. We characterize the effect of superconductivity on the precession damping and the anti-damping torques. We also predict the full non-linear characteristic of the Onsager counterparts of the torque, showing up via pumped charge and heat currents. For the latter, we predict a spin-pumping cooling effect, where the magnetization dynamics can cool either the nanomagnet or the superconductor.

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Spin pumping into superconductors: A new probe of spin dynamics in a superconducting thin film

Cited by 67 publications

References 54 publications

Spin-Pumping-Induced Inverse Spin Hall Effect in Nb/Ni80Fe20 Bilayers and its Strong Decay Across the Superconducting Transition Temperature

Spin-Pumping-Induced Inverse Spin Hall Effect in Nb/Ni80Fe20 Bilayers and its Strong Decay Across the Superconducting Transition Temperature

Probe of spin dynamics in superconducting NbN thin films via spin pumping

Nonlinear spin torque, pumping, and cooling in superconductor/ferromagnet systems

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