Low-temperature superlattice in monoclinic ${\mathrm{PbZr}}_{0.52}{\mathrm{Ti}}_{0.48}{\mathrm{O}}_3$

Transmission-electron microscopy has shown that the strongly piezoelectric material ${\mathrm{PbZr}}_{0.52}{\mathrm{Ti}}_{0.48}{\mathrm{O}}_3$ separates into two phases at low temperatures. The majority phase is the monoclinic phase previously found by x-ray diffraction. The minority phase, with a nanoscale coherence length, is a slightly distorted variant of the first resulting from the antiphase rotation of the oxygen octahedra about [111]. This work clears up a recent controversy about the origin of superlattice peaks in these materials, and supports recent theoretical results predicting the coexistence of ferroelectric and rotational instabilities.