Spontaneous magnetization curve of α-iron at high pressures determined using in situ neutron diffraction
Phys. Rev. B 113, 184440 – Published 11 May, 2026
DOI: https://doi.org/10.1103/vdnz-y1nk
Abstract
The temperature dependence of the magnetic moment of bcc α-iron was investigated over the range 300–950 K at pressures of approximately 2 and 6 GPa by in situ neutron powder diffraction. The isotope, whose neutron scattering length is approximately half that of naturally abundant Fe, was employed to enhance the relative contribution of magnetic scattering. Curie temperatures were determined to be 946(30) K, 838(50) K, and 740(40) K at 2.1, 6.0, and 6.7 GPa, respectively, defining a magnetic phase boundary described by . Upon heating at 6.7 GPa, the α–γ structural transition was observed to follow the magnetic transition. This transition sequence indicates that the magnetic phase boundary lies on the low-temperature side of the α–γ phase boundary. Accordingly, the α–γ transition corresponds to a structural transformation from paramagnetic bcc to paramagnetic fcc iron.
