Critical exponents in the (Formula presented) model, which describes localized-moment ferromagnets and antiferromagnets (N=2 in the Heisenberg model), are calculated from two-particle Green’s functions to first order in 1/N. For d=2+ɛ the results agree with earlier renormalization group calculations. For d=3 the leading 1/N corrections turn out to be very large at N=2. For d=4-ɛ the 1/N corrections are small at any N and insufficient to describe correctly the magnetic phase transition.
|Number of pages||4|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 1996|