Temperature-Dependent Raman Studies of Ba(Mg 1/3Ta2/3)O3

Microprobe Raman spectroscopy has been used to study ceramics and single-crystal fibres of BaMg1/3Ta2/3O3. According to x-ray diffraction, ceramics exhibit 1:2 order on the B sites whereas fibres remain disordered. The Raman spectra, however, are almost identical in both cases and are mostly consistent with 1:1 short-range order in nanoscale regions. Some extra lines of weak intensity originate from distortions in microstructures, probably providing charge compensation. Raman scattering measurements did not reveal the existence of 1:2 ordering in the nanoscale region in ceramics or single crystals.