Spin-½ Heisenberg Ferromagnet on Cubic Lattices: Analysis of Critical Properties by a Transformation Method

The high-temperature series expansions for the spin-{} Heisenberg ferromagnetic model on cubic lattices are analyzed by a transformation method. Evidence is presented suggesting that the susceptibility critical exponent (γ) and the gap parameter (2Δ) are both smaller than the original estimates obtained by Pad\'e approximant techniques. Specifically, we find that γ=1.36±0.04 and 2Δ=3.50±0.20. The error limits are to be taken as a reasonable confidence level rather than as a strict bound.