Single-phase formation mechanism and dielectric properties of sol-gel-derived Ba(Ti 0.2 Zr 0.2 Sn 0.2 Hf 0.2 Ce 0.2 )O 3 high-entropy ceramics

Single-phase Ba(Ti 0.2 Zr 0.2 Sn 0.2 Hf 0.2 Ce 0.2 )O 3 (BTZSHC) high-entropy ceramics (HECs) with the perovskite structure were successfully prepared via the sol-gel method. The results reveal that the as-prepared ceramics exhibit a single cubic phase belonging to the Pm 3?? m space group. The high entropy is the driving force of the formation of single-phase ceramics. A larger entropy ( AS mix ) and a negative enthalpy ( AH mix ) are conducive to the formation of single-phase compounds. Herein, AS mix = 0.323 R mole ???1 and AH mix = ???43.88 kJ/mol. The sluggish-diffusion effect ensures the thermal stability of high-entropy systems. Dielectric measurements reveal that the as-prepared BTZSHC high-entropy ceramics are relaxor ferroelectrics, and the degree of relaxor ( y ) is 1.9. The relaxor behavior of the as-prepared ceramics can be ascribed to the relaxation and thermal evolution of their polar units (PUs). The findings of this work provide a theoretical basis and technical support for the preparation of single-phase high-entropy ceramics.

Automated summary

Single-phase Ba(Ti 0.2 Zr 0.2 Sn 0.2 Hf 0.2 Ce 0.2 )O 3 (BTZSHC) high-entropy ceramics were successfully prepared via the sol-gel method. The high entropy is the driving force for single-phase formation and a large entropy and negative enthalpy contribute to the formation of single-phase compounds. The sluggish-diffusion effect ensures the thermal stability of the ceramic system. The ceramics exhibit relaxor ferroelectric behavior.