A single high-entropy pyrochlore-type compound (A2B2O7) was successfully synthesized, incorporating 8 different rare-earth cations at the A site and 2 different metal cations at the B site in equiatomic amounts [(8A1/8)2(2B1/2)2O7]. Powders with a nominal composition of (La1/8Sm1/8Nd1/8Pr1/8Y1/8Gd1/8Dy1/8Yb1/8)2(Hf1/2Zr1/2)2O7 were fabricated by glycine nitrate procedure (GNP). The GNP process yielded powders with low crystallinity and after subsequent calcination, a well crystalline ceramic powders were formed. The phase evolution was initially analyzed using X-ray diffraction (XRD). In situ high-pressure X-ray diffraction was employed to investigate the structural stability and high-pressure behavior of the A2B2O7 pyrochlore up to 25.8 GPa. Theoretical investigations of the high-entropy pyrochlore systems were performed and showed good agreement with the experimentally obtained results.
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