Quasi-long-range order in the random anisotropy Heisenberg model
PACS: 64.60.Cn, 75.10.Nr, 75.50.Kj
The random field and random anisotropy iV-vector models are studied with the functional renormalization group in 4 — e dimensions. The random anisotropy Heisenberg (N — 3) model has a phase with the infinite correlation radius at low temperatures and weak disorder. The correlation function of the magnetization obeys a power law (m(ri)m(r2)> ~ |ri — гг!"062'The magnetic susceptibility diverges at low fields as χ ~ jj-i+o.15« _ in the random field N-vector model the correlation radius is finite at the arbitrarily weak disorder for any N > 3.