1Key Laboratory of Advanced Transducers & Intelligent Control System (Ministry of Education), Taiyuan University of Technology, Taiyuan 030024 2College of Physics & Optoelectronics, Taiyuan University of Technology, Taiyuan 030024
Abstract：The zero-magnetic-field oscillation behavior of spin torque nano-oscillator (STNO) with a perpendicularly magnetized free layer with second-order uniaxial anisotropy is studied theoretically based on the Landau–Lifshitz–Gilbert–Slonczewski equation. It is demonstrated numerically that the second-order uniaxial anisotropy plays a significant role in the occurrence of a zero-magnetic-field steady-state precession, which can be understood in terms of the energy balance between the energy accumulation due to the spin torque and the energy dissipation due to the Gilbert damping. In particular, a relatively large zero-magnetic-field-oscillation current region, in which the corresponding microwave frequency is increased while the threshold current still maintains an almost constant value, can be obtained by modulating the second-order uniaxial anisotropy of the free layer. These results suggest a tunable zero-magnetic-field STNO, and it may be a promising configuration for STNO's applications in future wireless communications.
Kiselev S I, Sankey J C, Krivorotov I N, Emley N C, Schoelkopf R J, Buhrman R A and Ralph D C 2003 Nature425 380
[4]
Kaka S, Pufall M R, Rippard W H, Silva T J, Russek S E and Katine J A 2005 Nature437 389
[5]
Deac A M, Fukushima A, Kubota H, Machara H, Suzuki Y, Ysa S, Nagamine Y, Tsunekawa K, Diayaprawira D D and Watanabe N 2008 Nat. Phys.4 803
[6]
Dussaux A, Grimaldi E, Salles B R, Jenkins A S, Khavalkovskiy A V, Bortolotti P, Grollier J, Kubota H, Fukushima A and Yakushiji K 2014 Appl. Phys. Lett.105 022404
[7]
Zeng Z M, Amiri P K, Krivorotov I N, Zhao H, Finocchio G, Wang J P, Katine J A, Huai Y, Langer J, Galatsis K, Wang K and Jiang H 2012 ACS Nano6 6115
[8]
Chio H S, Kang S Y, Cho S J, Oh I Y, Shin M, Park H, Jang C, Min B C, Park S Y and Park C S 2014 Sci. Rep.4 5486
2016, Vol. 33 
