arXiv:cond-mat/0107583 · Physical review. B, Condensed matter
Ferromagnetic–spin-glass transition in a four-dimensional random-bond Ising model
Alexander K. Hartmann
Abstract
The four-dimensional $\ifmmode\pm\else\textpm\fi{}J$ random-bond Ising model is studied using ground-state calculations. System sizes up to ${N=6}^{4}$ spins are considered. Here it is found that the ferromagnetic--spin-glass transition occurs at a critical concentration ${p}_{c}=0.28(1)$ of the antiferromagnetic bonds, which is comparable to values found previously by high-temperature series expansions. The transition is characterized by a correlation-length exponent $\ensuremath{\nu}=1.0(1)$ and an order-parameter exponent $\ensuremath{\beta}=0.4(1).$ Thus, this transition is in a different universality class from four-dimensional bond percolation, where $\ensuremath{\nu}=0.678(50)$ and $\ensuremath{\beta}=0.639(20).$