MC Type Phase Structure and Temperature-Induced MC-C Transition in the As-Grown PMN-0.36PT Single Crystal

The phase structure in the as-grown PMN-0.36PT single crystal was studied and the temperature-induced domain evolution was investigated using a polarized light microscope (PLM). The crystal is identified to be MC type monoclinic based on the PLM results and tends to transform to cubic (C) phase directly through polarization rotation. The MC phase is metastable below Curie temperature (TC), but prone to tetragonal phase upon electric field poling or high-temperature annealing. We suppose that the formation of the MC phase structure is associated with the strain gradient originated from Ti4+ segregation and the special MC-C phase transformation style is mediated by the corresponding residual ferroelastic strain stored within the as-formed domain structure.