New Tetracritical Behavior in CsMnBr3

Abstract
The magnetic phase diagram of CsMnBr 3 has been determined from precise magnetization measurements. The single transition occurring in zero field splits into two successive transitions in a finite field applied in the c -plane. This indicates that the zero-field Néel point T N =8.32 K is a tetracritical point. The crossover exponents evaluated suggest that the tetracritical behavior is governed by the n =2 chiral universality.