The Film Tbdyfe Sandwich Membrane Gmi Effects

The large magnitudes of giant magneto impedance (GMI), together with a very high sensitivity at low fields, have prompted potential applications in information storage and micro-magnetic sensors. The anisotropy's magnitude and direction in the magnetic layer play a key role in GMI effect. If the anisotropy field is very small, there is no peak and the GMI curve monotonous declines; if the anisotropy field is very large, there is no GMI effect and the GMI curve is very smooth.In this paper, influence of TbDyFe film with magnetostrictive on the anisotropy field and the giant magneto impedance in sandwiched films are presented.First of all, the TbDyFe film is prepared on the substrate of Si by vacuum evaporation, and then has a further thermal vacuum treatment at 600℃. The magnetic properties and the structure are investigated in TbDyFe film. The annealed sample of thickness 600nm has a better structure than as-deposited sample, and X-ray diffraction shows ReFe₂ phase is formed after annealing. The annealed films have a strong magnetostrictive and initiate a large tensile stress, especially in a low magnetic fields.Secondly, the NiFeSiMnMo film is prepared on the substrate of the TbDyFe film and the interface diffusion is investigated in NiFeSiMnMo/TbDyFe films.The AES result shows the interface of the two layers in the annealed sample interpenetrated, forming a transition layer.At last, the sandwiched films are prepared on the substrate of the TbDyFe film. Due to magnetostrictive materials' stress effect on magnetic anisotropy which is believed to be critical for the giant magneto-impedance (GMI) effect, the GMI ratio is demonstrated to increase sharply in magnetic fields. The GMI ratio also increases when the samples are annealed at 280℃. But comparing with the as-deposited four layers film GMI ratio of the annealed sample decrease, it possibly attribute to the diffusion between NiFeSiMnMo and TbDyFe layers.