Effects of Bi2O3 -CaCu3Ti4O12 composite additives on micromorphology, static magnetic properties, and FMR linewidth Delta H of NCZ ferrites

摘要

NiCuZn (NCZ) ferrites have been widely used in non-reciprocal microwave/millimeter ferrite devices, such as circulators. With the development of microwave/millimeter devices and components to high frequency, miniaturization, and lightweight applications, NCZ ferrites have needed to satisfy the essential requirements of high saturation magnetization 4 pi M-s, low coercivity H-c, and low ferromagnetic resonance (FMR) linewidth Delta H. Herein, 0.1 wt% Bi2O3 and 0.0-3.5 wt% CaCu3Ti4O12 (CCTO) composite additives were introduced to NCZ ferrites, the influence of Bi2O3 -CCTO composite additives on micromorphology, static magnetic properties, and FMR linewidth Delta H of NCZ ferrites have been demonstrated in detail. The results show that increasing the CCTO amounts in NCZ ferrites, saturation magnetization 4 pi M-s monotonically decreases from 5484Gs to 4819Gs, and both coercive force H-c and FMR linewidth Delta H first decreases and then increases with minimums of 31A/m and 147Oe, respectively. In addition, the theory of spin-wave narrowing and the law of approach to saturation have been adopted for the separation calculation of FMR linewidth Delta H to the crystalline anisotropy linewidth Delta H-a and porosity induced linewidth Delta H-p. The sample with 0.1 wt% Bi2O3 and 1.5 wt% CCTO possesses high saturation magnetization 4 pi M-s (5321Gs), remanence B-r (200 mT), low coercivity H-c (31A/m), and low FMR linewidth Delta H (147Oe). The state-of-the-art NCZ ferrites with outstanding performances manifest significant applied potency for microwave/millimeter devices and components in phase array radar systems.