Magnetic Hysteresis and Electrical Impedance Spectra of Hard Magnetic SmCo5 and Soft Magnetic Co30Ag70 Composites

A Vibrating Sample Magnetometer (VSM) and a set-up for electrical impedance measurement in magnetic field were employed to study Co30Ag70 mechanical alloys with additions of 0%, 5% and 10% (mass fraction) hard magnetic SmCo5. With increasing SmCo5 content, the particulate composites exhibited an increase in the remanent magnetization when the coercive field remained rather constant. The electrical impedance of each composite did not show a large variation between 10 kHz and 100 kHz but rapidly rose with the increase in frequency from around 200 kHz to 1 MHz due to the skin effect. All impedance spectra were slightly shifted when the magnetic field of 3.3 kA/m was applied. The largest difference was observed in the case of Co30Ag70 without SmCo5 addition. The results confirmed the relationship between the magnetic softness of materials and their electrical impedance in magnetic field