Magnetic susceptibility of CsMnBr3 near the tetracritical point

CsMnBr3 is a stacked triangular antiferromagnet belonging to the Z2×S1 universality class. Recent predictions of a singularity in the zero-field uniform magnetic susceptibility χ have been tested by magnetization measurements for fields parallel and perpendicular to the hexagonal c axis. The temperature dependence was monotonic in both cases, while the phase transition was marked by a kink in χ. The absence of the predicted cusplike feature at TN is related to crossover behavior in a magnetic field, which is also not in agreement with the theoretical predictions.