A theory of the quantum Heisenberg spin-glass model with Dzyaloshinskii-Moriya interactions is presented in external magnetic fields for arbitrary spin. The imaginary-time functional-integral technique and the replica method are used. The model is investigated numerically within the static approximation. The smallest eigenvalue of the Hessian matrix is obtained by a generalized Almeida-Thouless method and the stability conditions are found, which give the upper and lower critical lines, respectively. Anisotropy-temperature phase diagrams are evaluated for different spin numbers in the case of no applied field. Thermodynamic functions, such as the entropy and the specific heat, are studied. Additionally, we can show that the local susceptibilities for different spin numbers are stabilized on a plateau at low temperatures by a small amount of the anisotropy.

• Received 8 January 1992

DOI:https://doi.org/10.1103/PhysRevB.47.254