Magnetic Neutron Scattering in Dysprosium Aluminum Garnet. I. Long-Range Order

Magnetic long-range order has been studied in antiferromagnetic dysprosium aluminum garnet (DAG) using coherent neutron scattering to measure the sublattice magnetization in the vicinity of the critical temperature. The value of the critical exponent $\beta$ in the power-law expression for the magnetization $M\sim {\left(\Delta T\right)}^{\beta }$ was found to be 0.26±0.02 for the temperature range $0.0010<\mathrm{}\Delta T_c<0.056\mathrm{}$. This is significantly lower than the theoretical estimate of 0.312 for the three-dimensional nearest-neighbor Ising model, with which DAG is compared.