Planes of Continuous-Wave Oscillations From an Electron Nanocontact Spin-Transfer Device

We have found that the frequencies of continuous-wave (CW) microwave oscillations in nanocontact spin-transfer (ST) devices occur in well-defined planes of frequencies, as a function of the dc current bias, the direction of the magnetic field, and the magnitude of the magnetic field. The frequency, f, of these technologically significant peaks for each magnetic field direction is described empirically by the equation of a plane, f=a|Boarr|+bI+c, where |Boarr| is the magnitude of the magnetic field, I is the dc bias current, and a, b, and c are constants of the plane. The primary frequency plane described by this equation is accompanied by a smaller secondary plane. The empirical equation describing the primary plane serves as a guide for efficiently locating CW oscillations within the independent variable space