Cluster-model-based design and synthesis for rutile-type Ti-Sn-Nb-Ta-Me-O (Me=Ga, Fe, Cr) high/medium entropy oxides

High entropy oxides have gained significant interest over the years due to their unique structural characteristics and correlated possibilities for control of functional properties. However, it is hard to forecast their properties and crystal structures due to the enormous inherent complexity and large number of potential combinations that characterize such systems. In this work, the reported high-entropy rutile-type Al-Cr-Nb-Ta-Ti-O system is first analyzed, and then a series of single-phase rutile-type Ti-Sn-Nb-Ta-Me-O (Me = Ga, Fe, Cr) compositionally complex oxides are designed via the cluster-plus-glue-atom model, and finally synthesized successfully by solid-state reaction method. The crystal structure of samples is determined by XRD, and the composition distribution is determined by EDS mapping. Results show that the cluster-plus-glue atom model can effectively guide the synthesis of rutile-structured high/medium entropy oxides with the assistance of geometric calculation, offering the corresponding solutions for the phase instability caused by the different crystal structures of raw materials and adjusting the lattice parameters of rutile structure by selecting various cations.