Polymorph Transitions and Structure Evolutions in Rare Earth Sesquioxides

In this work, polymorph transformations in rare earth sesquioxides were studied. It reveals that the transitions among A-, B-, and C-type structures were caused by varied rare earth ionic radii-induced ionic movement, and pictures of the transformation processes were demonstrated. It was determined that the A to B transition is reversible and those of A to C and B to C are not completely reversible. Additionally, we examined the phases in binary sesquioxides, and they are intimately related with the concentrations and rare earth ionic radii. These results offer new insights into the structure evolutions of rare earth sesquioxides, providing a reference for exploiting advanced sesquioxide functional materials.