Pressure-induced structural phase transition in bulk Zn0.98Mn0.02O by angular dispersive X-ray diffraction

Abstract

The high pressure induced phase transition in bulk Zn0.98Mn0.02O at ambient temperature have been investigated using angular-dispersive X-ray diffraction (ADXRD) under high pressure up to around 13.80 GPa. For loading run, in situ ADXRD measurements found that a wurtzite-to-rocksalt structural phase transition pressure of bulk Zn0.98Mn0.02O began at 7.35 GPa. The fitting of volume compression data to the third-order Birch-Murnaghan equation of state yielded that the zero-pressure isothermal bulk moduli and the first-pressure derivatives were 157(8) GPa and 8(3) for the B4 phase, respectively. When decompress bulk Zn0.98Mn0.02O to ambient pressure a large part of the bulk Zn0.98Mn0.02O reverted to the B4 phase and only a small amount of the metastable B1 phase remained. We have exhibits the pressure dependence of lattice constant a and c axis, and the normalized ratio c/a of the bulk Zn0.98Mn0.02O. Possible pressure-induced phase transition mechanisms were explored by examining the cell parameters and the internal structural parameter (u) with pressures. The effect of the 3d electrons of manganese to increase the nearest-neighbor distance of O to Zn (Mn) parallel to the c axis may be the main reason for the phase transition of bulk Zn0.98Mn0.02O. An increase in the u value with pressure indicates that the B4-to-B1 phase transformation in bulk Zn0.98Mn0.02O is likely via the hexagonal path. (C) 2014 Elsevier B.V. All rights reserved.