The complex ac dynamic magnetic susceptibility was used to study the spin-glass-like behavior in single-crystalline ${\mathrm{Cu}}_{0.44}{\mathrm{In}}_{0.48}{\mathrm{Cr}}_{1.95}{\mathrm{Se}}_4$ spinel. The broad maximum in the dc susceptibility at $44\mathrm{K}$ and the vanishing of the ac susceptibility second harmonic in the temperature range of $4.2–44\mathrm{K}$ suggest the spin-glass-like behavior. A large spin-glass-to-paramagnet transition points to the magnetically inhomogeneous state of the sample associated with nonstoichiometry. This is accompanied with the absence of the Curie-Weiss region in the temperature range of $44–360\mathrm{K}$, which reveals also an anomaly in the second and third harmonics of the ac susceptibility. This means that the formation of spin glasses takes place also in magnetic clusters above the freezing temperature $T_f=44\mathrm{K}$. The exchange constant of the spin-glass system estimated from the random energy model equals $26.4\mathrm{K}$. These observations are interpreted within the framework of the molecular field theory.

• Received 17 August 2007

DOI:https://doi.org/10.1103/PhysRevB.77.035207