Feco-based High-frequency Soft Magnetic Thin Films And Characteristics Of Study

With the development of electronic equipment and components towards the direction of miniaturization, high-frequency and integrated, functional materials, the foundation of electronic components, was put forward higher requirements. It is predicted that, to meet the needs of magnetic devices, high-frequency soft magnetic thin film has become the latest hot area of research of magnetic materials to meet the needs of magnetic devices, and will be widely used in magnetic recording heads, micro-inductors, micro-transformers, electromagnetic noise suppressors and magnetic sensors. So, FeCo-based high-frequency ferromagnetic thin films were prepared and studied.FeCo bilayers was prepared by DC magnetron sputtering method, CoNbZr and NiFe were used as the underlayers.The effects of preparation conditions, such as the Ar pressure, the sputtering powe, as well as the thickness of underlayer and FeCo,were discussed in the paper. The measurement results show that CoNbZr(2 nm)/FeCo(40 nm) and NiFe(3 nm)/FeCo(40 nm) have good soft magnetic properties. For CoNbZr(2 nm)/FeCo(40 nm), the coercivity of the easy axis ( H ce) is 3.9Oe, while the coercivity of the hard axis ( H ch) is 1.8Oe. The soft magnetic properties of NiFe(3 nm)/FeCo(40 nm) is H ce=3.7Oe, H ch=1.5Oe, H k=20~25Oe. The effect of oblique deposition on the magnetic properties was also investigated. When the oblique angle is 30°,in-plane magnetic anisotropy H k=80Oe, when the angle is up to 60°, H k~250Oe.In the mixture of Ar and O2 atmosphere, FeCoO and NiO were deposited by DC magnetron sputtering method, to form NiFe/FeCo/FeCoO, NiFe/FeCo/NiO multilayers. It is desire to increase the resistivity and the plane uniaxial anisotropy field H k of thin film sanples. Microstrip short-circuit method was used to test the high-frequency magnetic permeability of the samples, high resonance frequency over 2GHz was achieved in the multilayers, with the initial permeability over 400. Oxide layer thickness has the impact on the soft magnetic properties and the resisvity of the multilayers. In contrast to FeCo bilayers, H k of multilayers has small increase, is about 30-40Oe, and the resisvity is about 170μΩ? cm.