Dynamic magnetic characteristics of Fe78Si13B9 amorphous alloy subjected to operating temperature

• Operating temperature below 403 K impacts slightly on core loss when the B≤1.25 T.
• Core loss at power frequency and B>1.25 T increases with operating temperature.
• The real part of permeability increases with the rise of temperature.
• The imaginary part of permeability maxima shifts to lower frequency with temperature.

The operating temperature dependence of dynamic magnetic characteristics of the annealed Fe78Si13B9 amorphous alloy core was systematically investigated. The core loss, magnetic induction intensity and complex permeability of the amorphous core were analyzed by means of AC B–H loop tracer and impedance analyzer. It is found that the operating temperature below 403 K has little impact on core loss when the induction (B) is less than 1.25 T. As B becomes higher, core loss measured at high temperature becomes higher. For the cores measured at power frequency, the B at 80 A/m and the coercivity (Hc) at 1 T decline slightly as the temperature goes up. Furthermore, the real part of permeability (μ′) increases with the rise of temperature. The imaginary part of permeability (μ″) maxima shifts to lower frequency side with increasing temperature, indicating the magnetic relaxation behavior in the sample. In addition, with the rise in the operating temperature of the annealed amorphous core, the relaxation time tends to increase.