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We investigate the static and dynamic magnetic properties of a wedge Permalloy film. The spin distribution of the wedge film depends on the film thickness, ranging from the homogeneous in-plane to the out-of-plane component. The spin reorientation region of the wedge film is determined by using a magnetic force microscopy and magneto-optical Kerr effect measurements as well as the micromagnetic simulation. The dynamic properties of the spin distribution depending on the thickness are investigated by the microwave method. The acoustic and optical mode resonances of the wedge film are controlled by changing the direction of the microwave magnetic field and the stripe domains. The resonance frequency could be influenced by its domain structure and reveals the different anisotropies of the film. The results show that the spin distribution of the stripe domain depending on the thickness can be used to control the spin dispersion and precession frequency of the film for high-frequency applications.

Magnetic labels are one of the most important components in giant magnetoresistance (GMR) biodetection systems and affect detection signals directly. Many researchers have improved the detection performance of GMR biosensors by optimizing the properties of their magnetic labels, including size, shape, coercivity, and magnetization. In most studies, magnetic labels are usually spherical, and there is little research involving alternative shapes. In this work, we prepared spindlelike Fe3O4 nanoparticles (NPs) by hydrothermal and heating reduction. The as-prepared magnetic NPs were incorporated in the GMR biodetection system. An ultralow limitation of detection concentration of 0.05 ng/ml was achieved, which can be attributed to the shape anisotropy of the spindlelike magnetic particles. A wide linear work range, 0.05–1000 ng/ml, can be achieved by the use of the spindlelike Fe3O4 NPs in GMR biodetection. Moreover, the NPs exhibit good repeatability after multiple measurements, which can be attributed to the NPs’ stable and effective magnetic diffusion field. The use of spindlelike Fe3O4 NPs as magnetic labels in this work provides a new method for improving the sensitivity and repeatability of GMR biodetection.

FeCoCd thin films with 500 nm thickness are directly prepared through electrodeposition in the sulphate bath in which glycine and citric acid were added as complex agents. The composition, structure, and magnetic of FeCoCd films were investigated as a function of Cd2+ concentration, cathode current density, and deposition temperature. A wonderful soft magnetic FeCoCd film was prepared and its coercivity of easy axis and hard axis are 5 Oe and 4 Oe, respectively. The natural resonance frequency is about 3.0 GHz, which imply that the FeCoCd film is potential candidate for high frequency applications.