In situ neutron diffraction study of electric field induced structural transitions in lanthanum doped lead zirconate titanate

The structural reaction of La-doped PbZr1-xTixO3 (PLZT) with x = 0.44, 0.46 and 0.475 to an electric field was investigated by in situ neutron diffraction. The induced structural changes and the anisotropic displacement parameters were analysed. While the composition with a high Ti content shows a trend to tetragonal characteristics, PLZT with a low Ti content exhibits a rhombohedral response to the applied electric field. The intermediate composition with x = 0.46 appears rhombohedral in the unpoled state. Under the influence of an applied electric field, however, the response is similar to tetragonal PLZT (x = 0.475). With the investigated compositions the field induced processes are characterised. In the tetragonal composition the field dependent variation of the tetragonal lattice distortion is most pronounced. In rhombohedral PLZT (x = 0.44) the pseudorhombohedral lattice distortion exhibits the most significant changes. In the intermediate composition primarily atomic displacements are involved. Hence, a systematic change of the response to an applied electric field is observed while crossing the morphotropic phase boundary.