The 1/m expansion in spin glasses and the de Almeida-Thouless line
  It is shown by means of a 1/m expansion about the large-m limit of the m-vector spin glass that the lower critical dimension of the de Almeida-Thouless line in spin glasses is equal to the lower critical dimension of the large-m limit of the m-vector spin glass. Numerical studies suggest that this is close to six. 
M. A. Moore
cond-mat.dis-nn