Dynamic susceptibility in torus nanoring with canted external DC magnetic field

Abstract The dynamic susceptibility spectra of torus nanoring with a perpendicular or canted external DC magnetic field are studied by means of micromagnetic simulation. Due to the shape anisotropy of the torus nanoring, the system has a vortex spin structure when there is no external DC magnetic field, and the imaginary part of the dynamic susceptibility shows a single resonance peak. With the increase of DC magnetic field which is perpendicular to the plane of the ring, the resonant frequency decreases firstly and then increases monotonically. When the angle between the direction of the DC magnetic field and the center axis of the nanoring increases, the imaginary part of the magnetic susceptibility gradually shows one low frequency and three high frequency resonance peaks. By calculating the dynamic magnetic susceptibility of different parts of the nanoring, the corresponding region of each resonance mode is determined. Finally, we also discuss the effect of size on the magnetic susceptibility of the torus nanoring.