Study Of The High Frequency Power Loss Of Easy Plane Metallic Soft Magnetic Composites

Soft magnetic composites(SMCs)consisting of fine metal particles in a non-magnetic,insulating matrix,have great potential for integrated inductive and antenna applications.The dielectric and magnetic properties of soft magnetic composites can be tailored by selecting the matrix as well as the particle composition,size and concentration to reduce the device space footprint and improve performance.In particular,the magnetic anisotropy in composites can be controlled by selecting the particle shape and arrangement to overcome the Snoek limit,resulting in high magnetic permeability and high resonant frequency compared to conventional single-phase materials.In order to develop soft magnetic composites with high magnetic permeability,high resonant frequency,low hysteresis loss and low eddy current loss.The mechanism of high-frequency magnetism and power loss was investigated with the intention of finding the means to improve the magnetic permeability,resonant frequency and power loss from the principle.First,the ball milling conditions of carbonyl iron(CI)were initially screened.The types of grinding balls,rotational speed,and ball size ratio were screened.The final ball milling conditions were determined to be 400 r/min and 5 mm:3 mm = 1:1(w/w)Zr O balls.The diameter-thickness ratio increases and then decreases with the increase of ball milling time,and the magnetic permeability also has the same trend,and the maximum initial permeability is obtained at 9 h,which is about 25.2.Then,the theoretical model of the complex permeability of the flaky soft magnetic composites was established,and explained the variation of the initial permeability and the double-peaked structure magnetic spectrum.It is also pointed out that the two resonance peaks that usually appear in the magnetic spectrum are the natural resonance and the domain wall resonance,and on this basis,the relationship between the number of magnetic domains and the magnetic permeability and the relationship between the natural resonance and the domain wall resonance are discussed.According to the model,the fitting results and the experimental results basically fit together,which shows that our model is reasonable.Also,the high frequency power loss of SMCs with different diameter-thickness ratios was further investigated.The magnetic spectra of the samples with different diameter-thickness ratios were analyzed,and then the loss model of the sheet samples at high frequencies was developed,and the loss separation of these samples was carried out.The relationship between the diameter-thickness ratio,magnetic permeability and the three losses after separation was analyzed and discussed.The large diameter-thickness ratio can effectively improve the magnetic permeability and reduce the eddy current losses.The high permeability due to the large diameter-thickness ratio can also reduce the hysteresis loss.The magnetic domain differentiation caused in the process of obtaining large diameter-thickness ratio(ball milling),the change in the number of magnetic domain walls caused by this process also affects the excess losses.