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Qiu, Z.*; An, Toshu*; Uchida, Kenichi*; Hou, D.*; Shiomi, Yuki*; Fujikawa, Yasunori*; Saito, Eiji
Applied Physics Letters, 103(18), p.182404_1 - 182404_3, 2013/10
Times Cited Count:19 Percentile:61.88(Physics, Applied)Qiu, Z.*; Ando, Kazuya*; Uchida, Kenichi*; Kajiwara, Yosuke*; Takahashi, Ryo*; Nakayama, Hiroyasu*; An, Toshu*; Fujikawa, Yasunori*; Saito, Eiji
Applied Physics Letters, 103(9), p.092404_1 - 092404_4, 2013/08
Times Cited Count:112 Percentile:95.88(Physics, Applied)A platinum (Pt)/yttrium iron garnet (YIG) bilayer system with a well-controlled interface has been developed; spin mixing conductance at the Pt/YIG interface has been studied. A clear interface with good crystal perfection is experimentally demonstrated to be one of the important factors for an ultimate spin mixing conductance. The spin mixing conductance is obtained to be 1.310m at the well-controlled Pt/YIG interface, which is close to a theoretical prediction.
Kajiwara, Yosuke*; Uchida, Kenichi*; Kikuchi, Daisuke*; An, Toshu*; Fujikawa, Yasunori*; Saito, Eiji
Applied Physics Letters, 103(5), p.052404_1 - 052404_4, 2013/07
Times Cited Count:7 Percentile:30.83(Physics, Applied)Heat-current-induced manipulation of spin relaxation in YFeO under an in-plane temperature gradient is investigated. We show that the linewidth of the ferromagnetic resonance spectrum, i.e., the spin relaxation, in an YFeO film increases or decreases depending on the temperature-gradient direction and that this modulation is attributed to the spin-transfer torque caused by a thermally induced transverse spin-wave spin current in the YFeO film. The experimental results also show that the spin-current magnitude generated by spin pumping in an attached Pt film is inversely proportional to the square of the modulated Gilbert damping constant, consistent with a phenomenological spin-pumping model.
An, Toshu*; Yamaguchi, Kazuya*; Uchida, Kenichi*; Saito, Eiji
Applied Physics Letters, 103(5), p.052410_1 - 052410_3, 2013/07
Times Cited Count:6 Percentile:27.02(Physics, Applied)An, Toshu*; Vasyuchka, V. I.*; Uchida, Kenichi*; Chumak, A. V.*; Yamaguchi, Kazuya*; Harii, Kazuya; Oe, Junichiro*; Jungfleisch, M. B.*; Kajiwara, Yosuke*; Adachi, Hiroto; et al.
Nature Materials, 12(6), p.549 - 553, 2013/06
Times Cited Count:122 Percentile:96.36(Chemistry, Physical)Jungfleisch, M. B.*; An, Toshu*; Ando, Kazuya*; Kajiwara, Yosuke*; Uchida, Kenichi*; Vasyuchka, V. I.*; Chumak, A. V.*; Serga, A. A.*; Saito, Eiji; Hillebrands, B.*
Applied Physics Letters, 102(6), p.062417_1 - 062417_4, 2013/02
Times Cited Count:47 Percentile:85.88(Physics, Applied)Iguchi, Ryo*; Ando, Kazuya*; Qiu, Z.*; An, Toshu*; Saito, Eiji; Sato, Tetsuya*
Applied Physics Letters, 102(2), p.022406_1 - 022406_3, 2013/01
Times Cited Count:17 Percentile:58.33(Physics, Applied)We measured spatial distribution of spin pumping by nonreciprocal magnetostatic surface waves (MSSWs) using inverse spin Hall effect (ISHE) in a YIG/Pt system under local excitation. The local intensity of spin pumping by MSSWs shows center displacement of 1 mm from the center of a waveguide according to the reversal of a bias field, which is due to the nonreciprocal propagation of MSSWs over a macroscopic distance. The combination of spin pumping and ISHE enables electrical investigation of local spin dynamics in a magnetic insulator.
Hou, D.*; Qiu, Z.*; Harii, Kazuya; Kajiwara, Yosuke*; Uchida, Kenichi*; Fujikawa, Yasunori*; Nakayama, Hiroyasu*; Yoshino, Tatsuro*; An, Toshu*; Ando, Kazuya*; et al.
Applied Physics Letters, 101(4), p.042403_1 - 042403_4, 2012/07
Times Cited Count:73 Percentile:92.24(Physics, Applied)Inverse spin Hall effect has been investigated in bismuth(Bi)/permalloy(Py) bilayer films by using the spin pumping at room temperature. From the ferromagnetic-resonance-spectrum linewidth data, Bi is proved to be a good spin sink in our structure. We measured inverse spin Hall voltage and conductance of the Bi/Py bilayer and found that the inverse spin Hall current, , decreases with increasing the Bi thickness, which is in contrast to the former understanding in similar bilayer systems, e.g., Pt/Py. We constructed a model to explain the thickness dependence of quantitatively, in which spin transport modulation near Bi/Py interface is considered.
Uchida, Kenichi*; Adachi, Hiroto; An, Toshu*; Nakayama, Hiroyasu*; Toda, Masaya*; Hillebrands, B.*; Maekawa, Sadamichi; Saito, Eiji
Journal of Applied Physics, 111(5), p.053903_1 - 053903_8, 2012/03
Times Cited Count:27 Percentile:71.94(Physics, Applied)Using a Pt/YFeO (YIG) hybrid structure attached to a piezoelectric actuator, we demonstrate the generation of spin currents from sound waves. This "acoustic spin pumping" is caused by the sound wave generated by the piezoelectric actuator, which then modulates the distribution function of magnons in the YIG layer and results in a pure-spin-current injection into the Pt layer across the Pt/YIG interface. In the Pt layer, this injected spin current is converted into an electric voltage due to the inverse spin-Hall effect. The ISHE induced by the acoustic spin pumping is detected by measuring a voltage in the Pt layer at the piezoelectric resonance frequency of the actuator coupled with the Pt/YIG system. Our model calculation based on the linear response theory provides us with a qualitative and quantitative understanding of the acoustic spin pumping in the Pt/YIG system.
Uchida, Kenichi*; An, Toshu*; Kajiwara, Yosuke*; Toda, Masaya*; Saito, Eiji
Applied Physics Letters, 99(21), p.212501_1 - 212501_3, 2011/11
Times Cited Count:47 Percentile:84.82(Physics, Applied)A spin current generated from a surface acoustic wave (SAW) was observed in an YFeO/Pt(YIG)/Pt hybrid structure. At the YIG/Pt interface, a SAW generated in the YIG layer was found to pump a spin current into the Pt layer, which was detected through the inverse spin-Hall effect in the Pt. The YIG/Pt lateral structure combined with a piezoelectric wedge transducer enables the systematic investigation of the spin-voltage distribution due to the SAW in the YIG. Since the observed phenomenon has high affinity with SAW-based electronics, it will pave the way for constructing spintronic SAW devices.
Yamane, Yuta; Sasage, Kohei*; An, Toshu*; Harii, Kazuya*; Oe, Junichiro*; Ieda, Junichi; Barnes, S. E.*; Saito, Eiji; Maekawa, Sadamichi
Physical Review Letters, 107(23), p.236602_1 - 236602_4, 2011/11
Times Cited Count:45 Percentile:85.72(Physics, Multidisciplinary)Uchida, Kenichi*; Adachi, Hiroto; An, Toshu*; Ota, Takeru*; Toda, Masaya*; Hillebrands, B.*; Maekawa, Sadamichi; Saito, Eiji
Nature Materials, 10(10), p.737 - 741, 2011/10
Times Cited Count:222 Percentile:98.47(Chemistry, Physical)We show that, using a NiFe/Pt bilayer wire on an insulating sapphire plate, electrons in the wire recognize their position on the sapphire. Under a temperature gradient in the sapphire, surprisingly, the voltage generated in the Pt layer is shown to reflect the wire position, although the wire is isolated both electrically and magnetically. This non-local voltage due to the coupling of spins and phonons: the only possible carrier of information in this system. We demonstrate this coupling by directly injecting sound waves, which realizes the acoustic spin pumping. Our finding provides a persuasive answer to the long-range nature of the spin Seebeck effect, and it opens the door to "acoustic spintronics" in which sound waves are exploited for constructing spin-based devices.
Nishio, Takahiro*; An, Toshu*; Nomura, Atsushi*; Miyachi, Kosuke*; Eguchi, Toyoaki*; Sakata, Hideaki*; Lin, S.*; Hayashi, Nobuhiko; Nakai, Noriyuki; Machida, Masahiko; et al.
Physical Review Letters, 101(16), p.167001_1 - 167001_4, 2008/10
Times Cited Count:97 Percentile:93.25(Physics, Multidisciplinary)Superconductivity of nanosized Pb-island structures whose radius is 0.8 to 2.5 times their coherence length was studied under magnetic fields using low-temperature scanning tunneling microscopy and spectroscopy. Spatial profiles of superconductivity were obtained by conductance measurements at zero-bias voltage. Critical magnetic fields for vortex penetration and expulsion and for superconductivity breaking were measured for each island. The critical fields depending on the lateral size of the islands and existence of the minimum lateral size for vortex formation were observed.
Yamane, Yuta; Sasage, Kohei*; An, Toshu*; Harii, Kazuya*; Oe, Junichiro*; Ieda, Junichi; Barnes, S. E.*; Saito, Eiji; Maekawa, Sadamichi
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Yamane, Yuta; Sasage, Kohei*; An, Toshu*; Harii, Kazuya*; Oe, Junichiro*; Ieda, Junichi; Barnes, S. E.*; Saito, Eiji; Maekawa, Sadamichi
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