Nonmagnetic impurity effect on equilateral triangle spin tubes CsCrF4

Abstract

A chemical impurity substitution in gapped spin-liquid ground states often leads to antiferromagnetic long-range order. However, few experimental studies have been conducted on the substitution effect in gapless spin-liquid ground states. We performed X-ray diffraction and magnetic susceptibility experiments on equilateral triangle spin tubes composed of CsCr1−xAlxF4 (x = 0∼0.06). Because the gapless spin-liquid ground state is realized in CsCrF4 (CsCr1−xAlxF4 with x = 0), for x > 0, we expected competition between the geometrical spin frustration in each triangular plane and the impurity-induced antiferromagnetic long-range order. We verified that for x = 0∼0.06 no anomaly that indicates an antiferromagnetic long-range order appeared and that the gapless spin-liquid ground state was robust with respect to the effect of nonmagnetic impurity; we suggested that this is because geometrical spin frustration exists in the equilateral triangular plane.