17:15 〜 17:30
▼ [11p-M101-15] Giant spin-torque diode effect induced by heat induced magnetic anisotropy change
キーワード：spintronics, magnetic tunnel junction, spin torque diode effect
Magnetic tunnel junctions (MTJs) have been promising device for application in microwave frequency region, such as spin-torque diode effect [1]. Recently, Miwa et al. reported that the sensitivity of the spin-torque diode effect exceeds that of semiconductor diode [2]. To realize higher diode sensitivity, an efficient spin-torque is significant. We have reported that the Joule heating induces the efficient spin-torque due to the large and fast magnetic anisotropy change [3, 4]. In this study, we report that giant spin-torque diode sensitivity due to the heat induced anisotropy change.
The samples, buffer layer | IrMn (7.0) | CoFe | Ru | CoFeB | MgO barrier (1.0) | FeB (2.0) | MgO cap (0.5) | metal cap, were deposited on silicon substrates by the magnetron sputtering. The MTJ with the diameter of 190 nm was fabricated by an electron beam lithography. The spin-torque diode voltage of dc-biased MTJ was measured by the conventional measurement system of spin-torque diode effect [2]. Magnetic field of 50 mT was applied along the azimuthal angle of 11° and in-plane rotation angle from pinned layer magnetization of 135°. Figure 1 shows the microwave power dependence of diode voltage under the dc-bias voltage of approximately 400 mV. Linear power dependence was observed less than P = 10-8 W (red dashed line). As a result, we obtained the diode sensitivity of 1.4×106 V/W. This value is 300 times larger than the limit of semiconductor diode sensitivity of 3,800 V/W.
[1] A. A. Tulapurkar et al., Nature, 438, 339 (2005)
[2] S. Miwa et al., Nat. Mater, 13, 50 (2014)
[3] M. Goto et al., Nat. Nanotechnol, 14, 40 (2019)
[4] Y. Yamada et al., JSAP Autumn meeting, 18p-PB1-66, (2018)
The samples, buffer layer | IrMn (7.0) | CoFe | Ru | CoFeB | MgO barrier (1.0) | FeB (2.0) | MgO cap (0.5) | metal cap, were deposited on silicon substrates by the magnetron sputtering. The MTJ with the diameter of 190 nm was fabricated by an electron beam lithography. The spin-torque diode voltage of dc-biased MTJ was measured by the conventional measurement system of spin-torque diode effect [2]. Magnetic field of 50 mT was applied along the azimuthal angle of 11° and in-plane rotation angle from pinned layer magnetization of 135°. Figure 1 shows the microwave power dependence of diode voltage under the dc-bias voltage of approximately 400 mV. Linear power dependence was observed less than P = 10-8 W (red dashed line). As a result, we obtained the diode sensitivity of 1.4×106 V/W. This value is 300 times larger than the limit of semiconductor diode sensitivity of 3,800 V/W.
[1] A. A. Tulapurkar et al., Nature, 438, 339 (2005)
[2] S. Miwa et al., Nat. Mater, 13, 50 (2014)
[3] M. Goto et al., Nat. Nanotechnol, 14, 40 (2019)
[4] Y. Yamada et al., JSAP Autumn meeting, 18p-PB1-66, (2018)