Magnetic Properties of Ba4Zn2Fe36O60 Single Crystals

Abstract

The dc and microwave magnetic properties of single crystals of ${\mathrm{Ba}}_4{\mathrm{Zn}}_2{\mathrm{Fe}}_{36}{\mathrm{O}}_{60}(\mathrm{ZnU})$ were investigated. The saturation magnetization $\mathrm{\Vert \hspace{0.17em}}\mathrm{and}\mathrm{\hspace{0.17em}\perp \hspace{0.17em}}\mathrm{to}\mathrm{\hspace{0.17em}c}$ , anisotropy constant and anisotropy field were determined as a function of temperature from 4.2 to 600°K. $T_{\mathrm{C}}\text{\hspace{0.17em}=\hspace{0.17em}673±2°}\mathrm{K}$ . At room temperature ${\text{4πM}}_s\text{\hspace{0.17em}=\hspace{0.17em}3700\hspace{0.17em}}\mathrm{G}$ , $K_1{\text{\hspace{0.17em}=\hspace{0.17em} 1.4×10}}^6\hspace{0.17em}\mathrm{ergs}/{\mathrm{cm}}^3$ and $H^A\text{\hspace{0.17em}=\hspace{0.17em}9.6\hspace{0.17em}}\mathrm{kOe}$ . At 4.2°K ${\text{4πM}}_s\text{\hspace{0.17em}=\hspace{0.17em}6190\hspace{0.17em}}\mathrm{G}$ , $K_1{\text{\hspace{0.17em}=\hspace{0.17em}2.4×10}}^6$ and $H^A\text{\hspace{0.17em}=\hspace{0.17em}10\hspace{0.17em}}\mathrm{kOe}$ . A magnetic moment $n_{\beta }\text{\hspace{0.17em}=\hspace{0.17em}60}$ was computed from a collinear spin model, excellent agreement with $n_{\beta }\text{\hspace{0.17em}=\hspace{0.17em}60.5}$ , calculated from ${\sigma }_s\text{(H\hspace{0.17em}=\hspace{0.17em}∞, \hspace{0.17em}T\hspace{0.17em}=\hspace{0.17em}0)}$ . This result tends to confirm allignment of spins $\mathrm{\Vert \hspace{0.17em}}\mathrm{to}\mathrm{\hspace{0.17em}c}$ . Ferrimagnetic resonance linewidths of 210 Oe were measured on unpolished samples in the range 30–40 GHz. An anisotropy in electrical resistivity of 10⁷ Ω·cm ‖ and ${\text{4×10}}^3\mathrm{\hspace{0.17em}\Omega ·}\mathrm{cm}$ ⊥ to c was noted.