Analysis of power loss in Ni-Cu-Zn ferrites

Abstract

The power loss analysis was carried out for Ni-Cu-Zn ferrite samples with different content of NiO and ZnO. The power loss, Pc/spl nu/ decreases monotonically with increasing temperature and attains to a certain value at around 100/spl sim/120 degrees Celsius. The frequency dependence of Pc/spl nu/ can be explained by Pc/spl nu//spl sim/f, and n is independent of the frequency, f up to 1 MHz. The Pc/spl nu/ decreases with an increase in ZnO/NiO. The Pc/spl nu/ was separated to hysteresis loss, Ph and residual loss, (Pc/spl nu/-Ph). The temperature characteristics and compositional dependence of Pc/spl nu/ can be attributed to the Ph, while (Pc/spl nu/-Ph) is not affected by both temperature and ZnO/NiO. By analyzing temperature and composition dependence of Ph and initial permeability, u/sub i/ following equations could be formularized. u/sub i/u/sub 0/ = I/sub s//sup 2//(K/sub I/ + bs/sub 0/l/sub s/) (1), Wh = 13.5(I/sub s//sup 2//u/sub i/u/sub 0/) (2), where u/sub 0/ is permeability of vacuum, I/sub s/ saturation magnetization, K/sub I/ anisotropy constant, s/sub 0/ internal heterogeneous stress, l/sub s/ magnetostriction constant, b unknown constant. Wh hysteresis loss per one cycle of excitation (Ph = Wh*f). Steinmetz constant of Ni-Cu-Zn ferrites, m = 1.64/spl sim/2.2 is smaller than the one of Mn-Zn ferrites, which suggests the difference of loss mechanism between these materials.