High emission power and Q factor in spin torque vortex oscillator consisting of FeB free layer

Abstract

Microwave oscillation properties of spin torque vortex oscillators (STVOs) consisting of an FeB vortex free layer were investigated. Because of a high MR ratio and large DC current, a high emission power up to 3.6 µW was attained in the STVO with a thin FeB free layer of 3 nm. In STOs with a thicker FeB layer, e.g., 10 nm thick, we obtained a large Q factor greater than 6400 while maintaining a large integrated emission power of 1.4 µW. Such excellent microwave performance is a breakthrough for the mutual phase locking of STVOs by electrical coupling.

Self-Injection Locking of a Vortex Spin Torque Oscillator by Delayed Feedback

“…23). Here, the top layer of the synthetic antiferromagnetic reference layer with uniform in-plane magnetization is the spin polarizing layer.…”

Нагрузочные Характеристики Спин-Трансферного Наноосциллятора

“…Выражение (9) позволяет при конструировании усилителя мощности для СТНО количественно найти сопротивление нагрузки в режиме согласования, т. е. при максимуме отдаваемой в нагрузку мощности. Развитый в данной работе подход может также применяться для определения режима согласования в спин-трансферных осцилляторах вихревого типа, не использующих внешнее магнитное поле [12,13].…”

Temperature dependence of microwave oscillations in magnetic tunnel junctions with a perpendicularly magnetized free layer

“…25 As the current increases further the precession frequency continually decreases, and at the higher current levels, the FL magnetization may move towards the plane of the film. 17 We are unable to observe this because of large resistance (in the experiment the maximum current is set to 0.2 mA in case of damaging the device). Fig.…”

“…11 Recently, STNOs with perpendicular magnetic anisotropy (PMA) 12 in combination of high tunnel magnetoresistance (TMR) were demonstrated to be promising candidate for the development of practical applications. [13][14][15][16][17] For instances, Zeng et al 14 demonstrated large-power microwave oscillations in CoFeB-MgO magnetic tunnel junction (MTJ) with PMA free layer (FL) in the absence of any external magnetic fields. Tsunegi et al 17 reported an enhanced output power in FeB-based STNOs, but it still requires a large magnetic field ($kOe).…”

“…[13][14][15][16][17] For instances, Zeng et al 14 demonstrated large-power microwave oscillations in CoFeB-MgO magnetic tunnel junction (MTJ) with PMA free layer (FL) in the absence of any external magnetic fields. Tsunegi et al 17 reported an enhanced output power in FeB-based STNOs, but it still requires a large magnetic field ($kOe). Meanwhile, the linewidth in previous studies are still large for applications.…”