Magnetic properties of $\mathrm{Bi}\mathrm{Fe}{\mathrm{O}}_3$ (BFO) single crystals with rhombohedral symmetry $\left(R3c\right)$ were measured in the temperature range of $4.2–350\mathrm{K}$. Zero field cooled (ZFC) and field cooled magnetization curves split below $250\mathrm{K}$ with a sharp cusp around $50\mathrm{K}$ in the ZFC curves revealing spin-glass behavior in BFO single crystals. The observed coercive field increases with decreasing temperature, suggesting week ferromagnetism below $\sim 10\mathrm{K}$ and spin glass behavior below $\sim 120\mathrm{K}$. The cusps around the freezing temperature $\left[T_f\left(\omega \right)\right]$ which are frequency dependent confirm the spin-glass behavior in BFO single crystals with spin freezing temperature $(T_{\mathit{SG}}=29.4\pm 0.2\mathrm{K})$. The critical exponent $z\nu =1.38$ agrees rather well with experimental values in $\mathrm{La}{\mathrm{Mn}}_{0.5}{\mathrm{Fe}}_{0.5}{\mathrm{O}}_3$ $(z\nu =1.0)$ [K. De et al., J. Appl. Phys. 99, 13908 (2006)] and the mean field theory $(z\nu =2.0)$ of Kirkpatrick and Sherrington [Phys. Rev. B 17, 4384 (1970)].

• Received 17 September 2007

DOI:https://doi.org/10.1103/PhysRevB.77.144403