High-field magnetization measurements, with H ≤ 20T, yield the random-field Ising model (RFIM) specific heat behavior near the H-T phase boundary in Fe0.84Zn0.16F2. This sample, with x greater than the magnetic vacancy percolation threshold, Xv = 0.754, is in the concentration range that shows equilibrium neutron scattering line shapes at low temperature and |q| > 0, unlike samples for which x < Xv. The temperature derivative of the uniform magnetization shows the expected low-field random-field Ising scaling behavior for H ≤ 18 T. At H = 20 T, however, the peak temperature and amplitude are significantly suppressed, indicating a high-field RFIM region of the H-T phase diagram.
- High magnetic fields
- Random-field Ising model