Crystal Structure and Magnetism of Fe1−xTe (x=0.31)

Abstract

AbstractReaction of iron‐tellurium mixtures in the composition range from Fe0.41Te0.59 to Fe0.43Te0.57 followed by quenching to ambient temperature yields the high‐temperature δ phase Fe1−xTe (0.25<x<0.31). Single crystals of δ phase Fe1−xTe, with x=0.31(1), are obtained by reacting Fe−Te mixtures with nominal composition Fe0.43Te0.57 in closed ampoules at 973 K for 15 days before quenching to ambient temperature. In accordance with the chemical transport behavior of other phases in the iron‐tellurium system, the refined composition of the single crystals Fe1−xTe with x=0.31(1) suggests that crystallization and growth preferably occur in the tellurium‐rich part of the homogeneity range.The resulting crystals adopt a monoclinic crystal structure with unit cell parameters a=6.645(2) Å, b=3.8409(6) Å, c=11.314(3) Å, β=90.47(1)°, Z=4 (space group I2/m, non‐standard setting of C2/m). Single crystal structure refinement reveals a NiAs motif with partial occupation in every second iron layer along [001]. Magnetic susceptibility measurements indicate antiferromagnetic order below 400 K.