Study On The Magnetic Properties Of NiCu Films

In recent years,with the rapid development of the computer and information industries,magnetic materials have been combined with electronic components and optoelectronic devices to form microelectronic magnetic components.NiCu alloy is a film material widely used in GMR?Giant Magnetoresistance?.Because of its simple preparation process and low cost,it has attracted attention.In the laboratory,film preparation methods are commonly divided into two categories.one type requires a high vacuum environment,and the cost is higher.The other type does not require a high vacuum,and the cost is lower.Different film preparation methods will have a great impact on the performance of metal films.In this paper,the structure and magnetic properties of NiCu thin films are discussed based on two methods of electrodeposition and magnetron sputtering.The effects of the two preparation methods on the structure,morphology and magnetic properties of NiCu thin films were compared.It was found that the film prepared by the magnetron sputtering method had easier composition control and better film performance than the electrochemical deposition method.Compared with DC electrodeposition,pulse electrodeposition is easier to obtain a film with a flat surface,and it is more likely to have obvious resonance peaks,and the magnetic spectrum curve is smoother.The main contents are as follows:First,we studied the effects of Ni content in Ni_x Cu_1-x films on the structure,morphology and magnetic properties of the films,and the effects of Ni_x Cu_1-x films on the magnetic properties of the films after different annealing temperatures were studied.The increase of Ni content in Ni_xCu_1-x thin films leads to the increase of the saturation magnetization M_s,and the ferromagnetic resonance peak becomes obvious.Ni₇₇Cu₂₃film showed two ferromagnetic resonance peaks after heat treatment at 400oC.Secondly,we studied the structure,morphology,and magnetic properties of Ni₈₈Cu₁₂ thin films at different thicknesses and different annealing temperatures by magnetron sputtering.The experimental results show that the stripe domain structure appears at the film thickness of 210 nm of the Ni₈₈Cu₁₂.A stripe domain structure appeared at the film thickness of 105 nm for Ni₈₈Cu₁₂ thin film heat-treated at 300oC.The results of high-frequency magnetic spectroscopy show that the resonance peaks of Ni₈₈Cu₁₂ film will move in a small range with the increase of heat treatment temperature.Third,NiCu thin films with different deposition potentials and temperatures were prepared by electrodeposition of DC.The structure,morphology and magnetic properties of this films were discussed.During the discharge process the surface morphology of NiCu thin film will be flatter due to the rearrangement of metal ions and electrons.The experimental results show that ferromagnetic peaks became obvious at high deposition potentials.Finally,NiCu thin films with different duty cycle and deposition potentials were prepared by pulse electrodeposition.And the structure,morphology and magnetic properties of NiCu films were discussed.The surface of the films become flat as the duty cycle increases,and the resonance frequency increases first and then decreases.At70%duty cycle,as the deposition potential increases,the surface becomes flat,and the ferromagnetic resonance peak becomes more and more obvious.