High quality FeSb2 single crystal growth by the gradient freeze technique

A single crystal of FeSb2 about 5 mm in diameter and 10 mm in length with a tapering spire was grown by the gradient freeze technique combining the Bridgman technique and flux method using Sb-rich melts in sealed quartz ampoules. X-ray powder diffraction pattern of single crystal FeSb2 indicates that it is a single phase marcasite structure. Clear Laue spots and scanning electron microscopy photographs indicate good quality and uniform of the FeSb2 single crystal. Magnetic susceptibility of FeSb2 along b-axis does not show the diamagnetic to paramagnetic crossover, indicating the intrinsic susceptibility of FeSb2 determined on large single crystals differs from that of the smaller samples prepared by other techniques. The new method of gradient freeze is of great significance for the single crystal growth of FeSb2 like materials with a peritectic point.

► FeSb2 of 5 mm in diameter and 10 mm in length with a tapering spire was grown.
► We develop a new gradient freeze technique combining Bridgman and flux method.
► FeSb2 shows a single phase marcasite structure without any impurity phases.
► Clear Laue spot and microscopy photographs indicate good quality and uniform of FeSb2.
► The new gradient freeze is a good method for crystal growth of materials with a peritectic point.