Influence of atmosphere-induction and synergistic effect on the dielectric property of rutile-type (Ge0.2Mn0.2Ti0.2Sn0.2Mo0.2)O2 high-entropy oxides

A new high-entropy oxide, (Ge _0.2Mn _0.2Ti _0.2Sn _0.2Mo _0.2)O ₂ with rutile structure, was successfully synthesized using solid-state reaction method. The phase structure of the ceramic samples prepared forming a range of binary to quinary phase with increasing entropy were investigated, and the effects of atmosphere-induction and high-entropy synergistic behavior on the dielectric performance were studied. As the type of the cations increases, the temperature required to form a single rutile structure gradually decreases, while the dielectric properties of the ceramics gradually improved. The dielectric constant of the (Ge _0.2Mn _0.2Ti _0.2Sn _0.2Mo _0.2)O ₂ high-entropy oxide ceramics sintered in the nitrogen atmosphere at 1350°C is nearly 20 times higher of the ceramics sintered in the air. This significant enhancement can be attributed to the occurrence of two rutile structures and the generation of excessive oxygen vacancies as a result of high-entropy synergistic behavior under the nitrogen sintering atmosphere.