High-pressure formation of Mg_xZn_(1-x)O solid solutions with rock salt structure

摘要

X-ray diffraction with synchrotron radiation has been used for the first time to study the formation of Mg_xZn_(1-x)O (MZO) (0.33 ≤ x ≤ 0.83) solid solutions with rock salt structure at pressures up to 4.4 GPa and temperatures up to 1500 K. The chemical reaction between MgO and ZnO and a subsequent phase transformation of wurtzite solid solution (w-MZO) into rock salt one (rs-MZO) was observed at a stepwise heating at various pressures. The lattice parameters of rs-MZO solid solutions of different stoichiometries have been in situ measured at high pressures and temperatures. Unlike pure ZnO, the quenching of the reaction mixtures resulted in the formation of stabile MZO solid solutions with the rock salt structure. The phase diagram of the MgO-ZnO system at 4.4 GPa has been proposed based on the experimental data.