Spontaneous magnetization in the dipolar Ising ferromagnet LiTbF4

Abstract

The spontaneous magnetization $\mu$ in Bohr magnetons below $T_C=2.874\mathrm{}$ K in LiTb${\mathrm{F}}_4$ has been measured by magnetic Bragg scattering of neutrons. The data were normalized by comparing the magnetic Bragg scattering to the nuclear Bragg scattering at $T>\mathrm{}{T}_C$. The nuclear structure factors as well as the extinction corrections were determined at 295 and 100 K by a conventional neutron structure analysis from 304 and 196 nonsymmetry-related Bragg reflections, respectively. In the critical region $0.001<1-\frac{T}{T_C}<0.034\mathrm{}$, the data obeyed the power law $\mu =(19\mathrm{}\pm 2){(1-\frac{T}{T_C})}^{0.45\pm 0.03}$. The saturation moment is $8.9{\mu }_B$.