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SPIN HALL OSCILLATOR, MAGNETIC RECORDING DEVICE, AND CALCULATOR NEW

外国特許コード F200010232
整理番号 (S2019-0186-N0)
掲載日 2020年10月29日
出願国 世界知的所有権機関(WIPO)
国際出願番号 2020JP007010
国際公開番号 WO2020179493
国際出願日 令和2年2月21日(2020.2.21)
国際公開日 令和2年9月10日(2020.9.10)
優先権データ
  • 特願2019-037682 (2019.3.1) JP
発明の名称 (英語) SPIN HALL OSCILLATOR, MAGNETIC RECORDING DEVICE, AND CALCULATOR NEW
発明の概要(英語) This oscillator 100A comprises a spin current source 110 and a free layer 111 that is joined to the spin current source 100. The free layer 111 has a magnetization-hard axis parallel to a quantization axis of a spin current injected by the spin hall effect of the spin current source 110.
従来技術、競合技術の概要(英語) BACKGROUND ART
In recent years, a microwave oscillator utilizing spin torque has attracted attention because of its high Q value, high controllability of oscillation frequency by current, easy integration by CMOS technology, and so on. A microwave oscillator utilizing spin torque is called a spin torque oscillator (STO). STO utilizes precession of magnetization generated when a spin current is injected into the magnetic body.
The method of extracting microwaves from the precession of magnetization is roughly classified into 2 types. The 1 th method is a method of directly utilizing a high-frequency leakage magnetic field generated by precession magnetization. In the 2 th method, the precession of magnetization is extracted as an electric signal by utilizing the tunneling magneto-resistance (TMR) effect, converted into microwaves, and emitted. The 1 th method is simple in principle, but has a drawback that microwaves can be irradiated only at a short distance. On the other hand, the 2 th method must constitute a magnetic tunnel junction (MTJ) structure. However, since the microwave output per 1 devices is stronger than that of a method for extracting a leakage magnetic field, attention has been paid to.
STO is classified into 2 types according to the spin current generation method. The 1 th method utilizes spin polarization, and a spin current parallel to a charge current is generated by passing the charge current through the fixed layer of MTJ. At this time, the generation efficiency of the spin current is determined by the spin polarization rate of the fixed layer. Since the spin polarization rate does not exceed 1 in principle, the spin current generation efficiency is low, and a large current is required for oscillation. As an example, in Non-Patent Document 1, 110μA is required for oscillation at 0.9GHz. However, the structure of the free layer was standardized to have a length 50 nm, a width 50 nm, and a thickness 2 nm. When spin polarization is used, this large current passes through MTJ, which lowers the durability of MTJ and brings about a problem in the reliability of the oscillator.
The 2 th method utilizes the spin Hall effect, and a spin current perpendicular to the charge current is generated by passing the charge current through a spin current source composed of a material having strong spin orbit interaction. Therefore, a spin current source is joined to the magnetic layer which performs precession, and a charge current is applied to the spin current source in parallel with the joining surface. At this time, the generation efficiency of the spin current is determined by the spin hole angle of the spin current source and the ratio of the length and film thickness of the spin current source, and both parameters may exceed 1. Therefore, the spin current can be efficiently generated by the method utilizing the spin Hall effect. Further, since the spin Hall effect generates a spin current perpendicular to the charge current, the charge current for generating the spin current does not pass through MTJ. Thus, it is expected that the reliability of the oscillator can be improved.
  • 出願人(英語)
  • ※2012年7月以前掲載分については米国以外のすべての指定国
  • TOKYO INSTITUTE OF TECHNOLOGY
  • 発明者(英語)
  • PHAM Nam Hai
  • SHIROKURA Takanori
国際特許分類(IPC)
指定国 National States: AE AG AL AM AO AT AU AZ BA BB BG BH BN BR BW BY BZ CA CH CL CN CO CR CU CZ DE DJ DK DM DO DZ EC EE EG ES FI GB GD GE GH GM GT HN HR HU ID IL IN IR IS JO JP KE KG KH KN KP KR KW KZ LA LC LK LR LS LU LY MA MD ME MG MK MN MW MX MY MZ NA NG NI NO NZ OM PA PE PG PH PL PT QA RO RS RU RW SA SC SD SE SG SK SL ST SV SY TH TJ TM TN TR TT TZ UA UG US UZ VC VN WS ZA ZM ZW
ARIPO: BW GH GM KE LR LS MW MZ NA RW SD SL SZ TZ UG ZM ZW
EAPO: AM AZ BY KG KZ RU TJ TM
EPO: AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
OAPI: BF BJ CF CG CI CM GA GN GQ GW KM ML MR NE SN ST TD TG
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