Polarised Light Microscopy in Materials Characterisation

Polarised light microscopy can be used to study structural phase transitions in crystals with relative simplicity through birefringence measurements, with a sensitivity orders of magnitude greater than that obtainable by X-ray methods. The combination of a polarising microscope and a rotary compensator also allows contrast formation between different domains (twins) in ferroic materials such as ferroelectrics, ferroelastics, ferromagnetics and high critical-temperature superconductors, both in ceramic and single crystal forms. The addition of a heating and/or cooling stage to the polarising microscope, covering 4 to 2023 K, extends its applications to correlations with differential thermal analysis (DTA) data.