Phase diagram of the O(n) model with defects of “random local anisotropy” type

Abstract It is shown that the Imry-Ma theorem stating that in space dimensions d n -component vector order parameter ( O ( n ) model) leads to the long-range order collapse and to occurrence of a disordered state, is not true if an anisotropic distribution of the defect-induced random easy axes directions in the order parameter space creates a global anisotropy of the “easy axis” type. For a weakly anisotropic distribution of the easy axes, in space dimensions 2 ≤ d