Zero-field dynamics stabilized by in-plane shape anisotropy in MgO-based spin-torque oscillators
arXiv:1811.00106 · doi:10.1063/1.5081036
Abstract
Here we demonstrate numerically that shape anisotropy in MgO-based spin-torque nano-oscillators consisting of an out-of-plane magnetized free layer and an in-plane polarizer is necessary to stabilize out-of-plane magnetization precession without the need of external magnetic fields. As the in-plane anisotropy is increased, a gradual tilting of the magnetization towards the in-plane easy direction is introduced, favouring zero-field dynamics over static in-plane states. Above a critical value, zero-field dynamics are no longer observed. The optimum ratio of in-plane shape to out-of-plane uniaxial anisotropy, for which large angle out-of-plane zero-field dynamics occur within the widest current range, is reported.
References in corpus (16)
- Microwave Oscillations of a Nanomagnet Driven by a Spin-Polarized Current
- Current-driven Magnetization Reversal and Spin Wave Excitations in Co/Cu/Co Pillars
- Bias-driven large power microwave emission from MgO-based tunnel magnetoresistance devices
- Currents, Torques, and Polarization Factors in Magnetic Tunnel Junctions
- Anomalous Bias Dependence of Spin Torque in Magnetic Tunnel Junctions
- Ultralow-current-density and bias-field-free spin-transfer nano-oscillator
- Spin Transfer Dynamics in Spin Valves with Out-of-plane Magnetized CoNi Free Layers
- Ab initio studies of the spin-transfer torque in tunnel junctions
- Critical Field of Spin Torque Oscillator with Perpendicularly Magnetized Free Layer
- Thermally-Assisted Spin-Transfer Torque Dynamics in Energy Space
- Spin transfer torque oscillator based on asymmetric magnetic tunnel junctions
- Spin Torque Oscillators with Thermal Noise: A Constant Energy Orbit Approach
- Bias dependence of tunneling magnetoresistance in magnetic tunnel junctions with asymmetric barriers
- Self-Oscillation in Spin Torque Oscillator Stabilized by Field-like Torque
- Theoretical Study of Spin-Torque Oscillator with Perpendicularly Magnetized Free Layer
- Stable oscillation in spin torque oscillator excited by a small in-plane magnetic field