Intrinsic and Thermal Linewidths of Spin-Transfer-Driven Vortex Self-Oscillations

Narrow linewidth spin transfer driven vortex self-oscillations in Py/Cu/Py spin valves of elliptical cross section (160 nm 75 nm) are investigated by means of micromagnetic simulations. “GPmagnet”, a high performance GPU based micromagnetic package, is used for this purpose, allowing for 100 KHz spectral resolution at reasonable computational time. The variation of the linewidth with applied current ( A/cm A/cm ) is analyzed in the temperature range 0 K K. Linewidths around 1 MHz are found at K. At K, linewidths remain below 2 MHz for A/cm , whereas for larger currents the presence of two oscillation modes lead to a further linewidth increase.