Spin torque nano-oscillators with a perpendicular spin polarizer<xref rid="cpb_28_3_037503fn1" ref-type="fn">*</xref><fn id="cpb_28_3_037503fn1"><label>*</label><p>Project supported by the National Basic Research Program of China (Grant No. 2015CB921501) and the National Natural Science Foundation of China (Grant Nos. 11774260, 51671057, and 11874120).</p></fn>

Spin torque nano-oscillators with a perpendicular spin polarizer**

Project supported by the National Basic Research Program of China (Grant No. 2015CB921501) and the National Natural Science Foundation of China (Grant Nos. 11774260, 51671057, and 11874120).

Zheng Cuixiu¹, Chen Hao-Hsau², Zhang Xiangli², Zhang Zongzhi², Liu Yaowen^{1, †}

(a) Schematic of a STNO-based FSK modulation scheme by current pulse I(t) and magnetic field pulse h_z(t). The free layer is in-plane magnetized free layer and the polarizer layer is perpendicularly magnetized. (b) Schematic of frame transformation for an OP magnetization precession in the laboratory inertia frame and in the rotating frame with an angular frequency ω, respectively. The green and blue arrows denote the damping and STT vectors, respectively. The cray arrow denotes the virtual torque vector due to the coordinate transformation. h_rot is a virtual field along z-axis whose amplitude is associated to ω(m_z). Panels (c) and (d) show the E-field assisted FSK modulation scheme. Both the free layer and polarizer layer in the STNO have the perpendicular anisotropy. The additional oxide layer on the top of the free layer is used to apply the E-field and tunes the PMA.