Magnetic–crystallographic p,T‐phase diagram of Fe1.141Te: A high‐pressure neutron diffraction study

Abstract

The crystal and magnetic structures of Fe1.141Te have been studied by neutron powder diffraction in the temperature range from 5 to 106 K and pressures in the range from ambient to ≈2.7 GPa. The p,T‐phase diagram contains three phases with monoclinic, orthorhombic, and tetragonal symmetry. The monoclinic phase was found to be stable for T ≲ 57 K and p < 0.4 GPa while the orthorhombic phase is stable for T ≲ 63 K and 0.4 ≲ p ≲ 2.16 GPa. The tetragonal phase is stable at high temperatures and becomes stable down to the lowest measured temperatures for p > 2.16 GPa. The monoclinic phase shows commensurate bicollinear antiferromagnetic order with propagation vector k = (½ 0 ½), while the orthorhombic phase is incommensurately antiferromagnetically ordered with propagation vector k = (½‐δ 0 ½). The δ−parameter increases linearly with the pressure for 0.4 ≲ p ≲ 2.16 GPa. Pressure‐induced ferromagnetic order was observed in the tetragonal phase for p ≳ 2.1 GPa and temperatures less than ∼68 K, depending on the pressure.