Crystal structure, microstructure, and magnetic properties of Ba3-xNdxCo2Fe24O41 hexaferrite ceramics with enhanced magnetic anisotropy

Abstract

Crystal structure, microstructure, static and dynamic magnetic properties of Ba3-xNdxCo2Fe24O41 (x = 0.0, 0.1, 0.2, 0.3, 0.4, and 0.5) ceramics were investigated. Samples were prepared via sintering at 1250 °C for 4 h, and XRD results revealed their crystal structure after Nd substitution. With the increase in Nd3+ ion dopant content, particle porosity increased, leading to slight decrease in volume density. Static magnetic data showed the weak effect of Nd-substitution on saturation magnetization strength and a slight increase in coercivity (from 52 Oe to 75 Oe at x = 0–0.5), while out-of-plane magnetic anisotropy rose significantly (from 10.1 kOe to 14.5 kOe at x = 0–0.5). Dynamic magnetic tests demonstrated noticeable decrease in permeability (from 17 to 8), whereas cutoff frequency increased from 0.8 GHz to 1.9 GHz and the maximum Snoek product reached 18.8 GHz for the sample with x = 0.4. The fitting of real part of permeability using domain wall resonance and natural resonance models revealed that resonance frequency and out-of-plane anisotropy both increased with Nd-substitution. Moreover, despite Nd doping, samples maintained low magnetic loss and high Q value within higher frequency range. Therefore, findings of this study provide a pathway to development of substituted Z-type barium (Co2Z) ferrites for high frequency applications.