Ramos, R.*; 吉川 貴史*; Anadn, A.*; Lucas, I.*; 内田 健一*; Algarabel, P. A.*; Morelln, L.*; Aguirre, M. H.*; 齊藤 英治; Ibarra, M. R.*
AIP Advances (Internet), 7(5), p.055915_1 - 055915_7, 2017/05
We report temperature dependent measurements of the spin Seebeck effect (SSE) in multilayers formed by repeated growth of a FeO/Pt bilayer junction. The magnitude of the observed enhancement of the SSE, relative to the SSE in the single bilayer, shows a monotonic increase with decreasing the temperature. This result can be understood by an increase of the characteristic length for spin current transport in the system, in qualitative agreement with the recently observed increase in the magnon diffusion length in FeO at lower temperatures. Our result suggests that the thermoelectric performance of the SSE in multilayer structures can be further improved by careful choice of materials with suitable spin transport properties.
Ramos, R.*; 吉川 貴史*; Aguirre, M.*; Lucas, I.*; Anadn, A.*; 小宅 教文*; 内田 健一*; 安立 裕人; 塩見 淳一郎*; Algarabel, P. A.*; et al.
Physical Review B, 92(22), p.220407_1 - 220407_5, 2015/12
Spin Seebeck effects have been investigated in highly crystalline magnetic multilayer films. Voltage as well as power generated by the spin Seebeck effect were found to be significantly enhanced with increasing the number of layers, . This voltage enhancement defies the simple understanding of the spin Seebeck effect and suggests that spin current flowing between the magnetic layers in the thickness direction plays an important role in the multilayer SSE systems and the observed voltage enhancement.
Ramos, R.*; Aguirre, M. H.*; Anadn, A.*; Blasco, J.*; Lucas, I.*; 内田 健一*; Algarabel, P. A.*; Morelln, L.*; 齊藤 英治; Ibarra, M. R.*
Physical Review B, 90(5), p.054422_1 - 054422_6, 2014/08
We report a complete characterization of the anomalous Nernst effect (ANE) and its relationship with the anomalous Hall effect (AHE) in FeO. By combining full thermoelectric and electric transport measurements as a function of temperature, we have verified that the universal scaling relation between the anomalous Hall and diagonal conductivities, observed in materials with bad-metal-hopping type of conduction, is also applicable to the thermoelectric transport. We further show that the ANE and AHE are commonly related through the Mott relation, therefore demonstrating its validity for anomalous transport phenomena in materials with conduction in the dirty regime.
Ramos, R.*; 吉川 貴史*; 内田 健一*; 安立 裕人; Lucas, I.*; Aguirre, M.*; Algarabel, P.*; Morelln, L.*; 前川 禎通; 齊藤 英治; et al.
Applied Physics Letters, 102(7), p.072413_1 - 072413_5, 2013/02
We report the experimental observation of the spin Seebeck effect in magnetite thin films. The signal observed at temperatures above the Verwey transition is a contribution from both the anomalous Nernst (ANE) and spin Seebeck (SSE) effects. The contribution from the ANE of the FeO layer to the SSE is found to be negligible due to the resistivity difference between FeO and Pt layers. Below the Verwey transition, the SSE is free from the ANE of the ferromagnetic layer and it is also found to dominate over the ANE due to magnetic proximity effect on the Pt layer.
Garin, P.*; Diegele, E.*; Heidinger, R.*; Ibarra, A.*; 實川 資朗; 木村 晴行; Mslang, A.*; 室賀 健夫*; 西谷 健夫; Poitevin, Y.*; et al.
Fusion Engineering and Design, 86(6-8), p.611 - 614, 2011/10
Mosnier, A.*; Beauvais, P. Y.*; Branas, B.*; Comunian, M.*; Facco, A.*; Garin, P.*; Gobin, R.*; Gournay, J. F.*; Heidinger, R.*; Ibarra, A.*; et al.
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.588 - 590, 2010/05
The objectives of the IFMIF/EVEDA project are to produce the detailed design of the entire IFMIF facility, as well as to build and test a number of prototypes, including a high-intensity CW deuteron accelerator (125 mA @ 9 MeV). Most of the accelerator components (injector, RFQ, superconducting RF-linac, transport line and beam dump, RF systems, local control systems, beam instrumentation) are designed and provided by European institutions (CEA/Saclay, CIEMAT, INFN/LNL, SCK-CEN), while the RFQ couplers, the supervision of the control system and the building including utilities constructed at Rokkasho BA site are provided by JAEA. The coordination between Europe and Japan is ensured by an international project team, located in Rokkasho, where the accelerator will be installed and commissioned. The design and R&D activities are presented, as well as the schedule of the prototype accelerator.