Ferromagnetic Resonance in Ba4Zn2Fe36O60 (ZnU) and Mn-Substituted ZnU Single Crystals

Abstract

Resonance experiments were performed on Ba₄Zn₂Fe₃₆O₆₀ (ZnU) and Mn‐substituted ZnU single crystal spheres using a reflection technique and transverse pumping. The influence of surface polish on linewidth was studied from 26.5–40 GHz at 300°K. In general, ΔH was found to be only slightly dependent upon frequency. The lowest linewidth was 18.5 Oe measured on a Mn‐substituted ZnU sample at 26.5 GHz. 4πM_s, H^A, ΔH, and γ_eff values are presented at 4.2°, 77°, and 300°K. A bandpass filter was constructed using a spherical resonator in an orthogonal configuration. The electrical characteristics are as follows: (1) Passband insertion loss, L_a=3.1–5.4 dB; (2) 3 dB bandwidth =200–380 MHz; (3) Stopband attenuation =30 dB, except spurious modes which are greater than 10 dB below main resonance.