A high-precision, multimethod Monte Carlo study of the static exponents of the $O\left(3\right)$ classical Heisenberg ferromagnet yields an estimate for the critical temperature of $T_c\approx 1.4427\pm 0.0002$ from which it is conjectured that $T_c=1\mathrm{}/\ln \left(2\right)$. It is shown from finite-size scaling of the data that the specific heat is singular for this model, with $\alpha =0.0750\mathrm{}\pm 0.002$, $\nu =0.642\mathrm{}\pm 0.002$, $\beta =0.328\mathrm{}\pm 0.001$, and $\gamma =1.270\mathrm{}\pm 0.001$. This result is confirmed by comparing the universality scaling of the full order parameter curve for three possible values of $\nu$.

• Received 8 September 1995

DOI:https://doi.org/10.1103/PhysRevLett.76.1352