Use of in situ TEM experiments for phase transition studies

We present various in situ TEM experiments performed for phase transition studies. Such original experiments require original stages that are presented before each discussion. The first part concern TEM studies of ferroic domain switches carried out on ferromagnetic and ferroelectric/ferroelastic compounds. Then we present in situ TEM experiments carried out on the tetragonalorthorhombic structural phase transition in YBa2Cu 3O6+x under a controlled oxygen pressure. The last part of the paper deals with the incommensurate phase of Quartz. We present TEM experiments concerning the triple-q to single-q phase transition that have been performed using an heating straining stage and other original results evidencing the ferroelectric properties of the incommensurate phase