Temperature versus concentration phase diagram of Mg- and Si-doped CuGeO 3

Abstract

We studied the temperature versus concentration ( T– x) phase diagram in Cu 1− x Mg x GeO 3 by susceptibility measurements, synchrotron X-ray diffraction and neutron diffraction and the first-order phase transition between dimerized-antiferromagnetic and uniform-antiferromagnetic phases reported by Masuda et al. [Phys. Rev. Lett. 80 (1998) 4566] was established. We found that the T– x phase diagram of Cu 1−xM x GeO 3 (M= Zn, Ni) is similar to that of Cu 1− x Mg x GeO 3, while that of CuGe 1− x Si x O 3 is qualitatively different.