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A big enough transverse magnetic field applied in soft magnetic ferrite toroid can magnetize the ferrite to saturation in transverse direction and almost completely suppresses magnetic domain structures in the ferrite, the response to the longitudinal alternating electromagnetic field changes from the original domain wall displacements and spin rotations to the precession of magnetization around the transverse field and the hysteresis loss disappears in the ferrites. Both theoretical and experimental results indicate that the permeability and magnetic losses in the ferrite can be tuned by adjusting the transverse magnetic field. A higher Q value with relatively lower permeability can be achieved by increasing the transverse field, which ensures the ferrite can be operated at high frequencies with very low magnetic losses.

In this paper, we investigated the structure of SmCo films with different thickness and the effects of Cr buffer layer on the structure and morphology of SmCo/Cu thin films. Our data revealed that the magnetic properties of the samples were enhanced by the crystallization of SmCo which was promoted by the optimized Cu underlayers. We also found that the surface roughness can be decreased by Cr layer and the texture can be improved by prolonging the annealing time for thick SmCo film. Thus, we concluded that the magnetic properties of SmCo/Cu films can be further optimized by varying the thickness of Cr buffer layers.

Nitrogen (N)-doped ZnO thin films have been deposited on Si (100) substrates by pulsed laser deposition under different N2 pressures. The optical and magnetic properties of N-doped ZnO films have been studied with photoluminescence, Raman spectroscopy, and vibrating sample magnetometer. Photoluminescence and Raman studies reveal that N2 pressure affected the defects of N-doped ZnO films. Under 10 Pa N2 pressure, N substitutes O and forms NO acceptor. Zn interstitials are main compensating donors. Under higher N2 pressures, N not only substitutes O but also forms N2O molecules in N-doped ZnO films. Zn antisizes are compensating donors. In additional, Zn vacancies are formed and the concentration increases with increasing N2 pressure. Magnetic properties of these films show that there are two distinct ferromagnetic mechanisms: the origin of ferromagnetism in the ZnO:N-10 Pa film is Zn interstitial, while Zn vacancy leads to ferromagnetism in the ZnO:N-50 Pa film.