| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1593010 | Solid State Communications | 2011 | 5 Pages |
The double-time temperature-dependent Green’s function method is used to determine the Néel temperature of a Heisenberg antiferromagnet with easy axis XXZXXZ anisotropy on a DD-dimensional bcc lattice. Exact equations within the random phase approximation (RPA) and Callen approximation (CA) in terms of generalized hypergeometric functions valid for arbitrary DD, SS, and η≥1η≥1 are given. Analytical and numerical results presented here strongly suggest that, for D≥2D≥2, the CA gives a higher critical temperature. It is also shown that the RPA set of self-consistent equations yields a Néel temperature closer to the experimental value for compound (CH3NH3)2MnCl4.
► Tyablikov’s and Callen’s methods are compared. ► The Néel temperature is determined by using DD-dimensional Watson-like integrals. ► Exact solutions in terms of generalized hypergeometric function are given. ► Callen’s approach yields higher critical temperature for D≥2D≥2. ► Tyablikov’s method gives Néel temperature closer to the experimental value for compoung (CH3NH3)2MnCl4.
