Yuki Shiomi

Critical suppression of spin Seebeck effect by magnetic fields

The longitudinal spin Seebeck effect (LSSE) in

One-dimensional spinon spin currents

\mathrm{Pt}/{\mathrm{Y}}_{3}{\mathrm{Fe}}_{5}{\mathrm{O}}_{12}\phantom{\rule{0.28em}{0ex}}(\mathrm{YIG})

Magnetic thermal conductivity far above the Néel temperature in the Kitaev-magnet candidate α−RuCl3

junction systems has been investigated at various magnetic fields and temperatures. We found that the LSSE voltage in a Pt/YIG-slab system is suppressed by applying high magnetic fields and this suppression is critically enhanced at low temperatures. The field-induced suppression of the LSSE in the Pt/YIG-slab system is too large at around room temperature to be explained simply by considering the effect of the Zeeman gap in magnon excitation. This result requires us to introduce a magnon-frequency-dependent mechanism into the scenario of LSSE; low-frequency magnons dominantly contribute to the LSSE. The magnetic field dependence of the LSSE voltage was observed to change by changing the thickness of YIG, suggesting that the thermospin conversion by the low-frequency magnons is suppressed in thin YIG films due to the long characteristic lengths of such magnons.

Spin current generation from sputtered Y3Fe5O12 films

Eiji Saitoh† Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577, Japan The Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195, Japan and WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan (Dated: September 26, 2016)

Signature of magnon Nernst effect in an antiferromagnetic insulator

The Kitaev quantum spin liquid on a honeycomb lattice has received much interest in magnetism, mainly because of the possibility of emergence of novel excitations called Majorana quasiparticles. The quest is under way to realize this exotic state in actual materials. One of the promising materials is the layered honeycomb material RuCl

Transverse thermoelectric effect in La0.67Sr0.33MnO3|SrRuO3 superlattices

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Universal scaling for the spin-electricity conversion on surface states of topological insulators

, for which the signatures of the Majorana quasiparticles have been reported. Here, the authors investigate the magnetic thermal conductivity of RuCl

Paramagnetic spin pumping.

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Reducing galvanomagnetic effects in spin pumping measurement with Co75Fe25 as a spin injector

along with bulk thermodynamic measurements. They find that in the temperature range on the order of the Kitaev-coupling strength anomalous heat conduction takes place, which correlates with the growth of the magnetic specific heat. The result is consistent with the propagation of magnetic excitations, likely itinerant Majorana quasiparticles, driven by Kitaev coupling.

Dispersion-type Hall resistance in InSb|Pt hybrid systems

Spin current injection from sputtered yttrium iron garnet (YIG) films into an adjacent platinum layer has been investigated by means of the spin pumping and the spin Seebeck effects. Films with a thickness of 83 and 96 nanometers were fabricated by on-axis magnetron rf sputtering at room temperature and subsequent post-annealing. From the frequency dependence of the ferromagnetic resonance linewidth, the damping constant has been estimated to be