New phase diagram of Zn-doped CuGeO3

A series of high-quality single crystals of ${\mathrm{Cu}}_{1-x}{\mathrm{Zn}}_x\mathrm{Ge}{\mathrm{O}}_3$ have been examined by neutron-scattering techniques. An antiferromagnetic (AF) ordering is confirmed for four samples in the range $0.009<~x<~0.047$, in complete agreement with previous reports. We show that the spin-Peierls (SP) phase transition persists to 4.7% Zn, whereas previous magnetic-susceptibility measurements reported a deterioration of the SP transition above 2% Zn. We present some details of the successive transitions upon lowering temperature into the spin-Peierls phase which is followed by a transition into an antiferromagnetically ordered phase. Below the Néel temperature we observe the coexistence of the SP lattice dimerization and AF states.