Qualitative and quantitative analysis of twin structure in top seeding melt texture growth-processed YBa2Cu3O7−δ ceramics

The present study reviews the techniques suitable for twin characterisation in TSMTG-processed ceramics: Conventional Transmission Electron Microscopy, Scanning Electron Microscopy (backscattered electrons images), and X-ray diffraction (pole figures). Optical microscopy can not be used because twin spacing in the studied ceramics are smaller than this technique resolution. A difference between SEM looking like twins average spacing and TEM twins average spacing is pointed out and some explanations are envisaged. Concerning X-ray diffraction, rocking curves can not be used to characterise twins in textured ceramics, but pole figures allow qualitative measurements.