Measuremengt Of Microwave Magnetic Property Of Magnetic Thin Film By Coplanar Waveguide

With the rapid development of modern science and technology,the high performance magnetic devices which design and manufacture by magnetic thin film materials have the characteristics of small size, high accuracy and speed fast and so on, widely used in the field of micro-electromechanical systems, microwave communications systems, electronic warfare systems and information storage systems. Along with operating frequency increasing of electronic devices, a large number of magnetic thin films used in the microwave band, Accurate characterization of microwave electromagnetic parameters such as magnetic permeability and microwave ferromagnetic resonance linewidth is not only the basis for its application, but also the basis to research dynamics of High-frequency magnetization of magnetic thin film. Thus accurate characterization of microwave magnetic thin film magnetic properties(including microwave magnetic permeability and ferromagnetic resonance linewidth) has very important significance.Firstly, The calculation model using coplanar waveguide transmission line to test the permeability of the film was institued. According lumped circuit model combined with microwave transmission line network scattering parameters derived the formula using scattering parameters obtained by test to calculate the permeability of the magnetic thin film microwave spectrum. And then designed a Grounded coplanar waveguide test fixture, simulated and optimized its size, the determined sizes of the cpw test fixture are:the materia of substrate is Roggers5880 which thickness is 0.508 mm, the bandwidth of the intermediate signal conductor GCPW is 1.2mm, the gap between the signal conductor and the ground plate on both sides is 0.1mm. The simulated and calculated results which loaded the magnetic thin film to test fixture show that the calculated magnetic spectrum is consistent with the input magnetic spectrum when simulation.Using GCPW fixture tested the magnetic spectrum of isotropic Ni Fe films, anisotropic Ni Fe films and tilt sputtering of Ni Fe films, and fitted with theoretical magnetic spectrum formula. The results showed that all Ni Fe film tested magnetic spectra were calculated can be well fitted by using the theoretical formula, and verifyied the validity of the test fixture and test theories. Test results showed that the resonance frequency of the isotropic Ni Fe film is 0.9GHz, the fitted tsaturation magnetization sM =686 k A m, the anisotropy field kH=0.608 k A m, the damping coefficient a=0.02. Anisotropic Ni Fe film resonant frequency is 2GHz,sM =495 k A m, kH=5.2 k A m, the damping coefficien a=0.02.Tilt sputtering Ni Fe film resonance frequency is 2.2GHz, sM =724 k A m, kH=5.6 k A m, the damping coefficient a=0.012.The relationship during the energy of magnetic thin film ferromagnetic resonance absorption and applied magnetic field was used to established the method using CPW fixture to test the ferromagnetic resonance linewidth of magnetic thin film. Using the test fixture of GCPW tested the variation between ferromagnetic resonance frequency and the external magnetic field of ordinary Ni Fe film and heating conditions plated Ni Fe film. The results showed that the resonant frequency moved to the high-frequency along with increasing magnetic field. The ordinary Ni Fe film at 3GHz, 3.5GHz, 4GHz frequency ferromagnetic resonance linewidth were 41.7Oe, 45.9Oe, 50.4Oe,the Ni Fe film manufactured under heated conditions at 3GHz, 3.5GHz, 4GHz frequency ferromagnetic resonance linewidth were 90 Oe,100.3Oe, 110.3Oe.