THE INTERMEDIATE PHASE OF QUARTZ .2. BEHAVIOR NEAR THE 1ST-ORDER TRANSITION-TEMPERATURE

The behavior of the transition of quartz in a range of 0. 1 K immediately above the transition temperature (T//c) was studied mainly in the cooling run from the intermediate phase (IP) to the alpha phase. Rod-like entities parallel to the c-axis are formed, the thickness being an order of 30-100 mu m. They cause an inhomogeneous strain in the crystal. This texture (super-modulated structure) is intrinsic since it exists more clearly when the alpha phase does not coexist in the specimen. It is transformed into the alpha phase at T//c. It is suggested that the entity is a commensurate phase.