Novel high-entropy (La 1/6 Nd 1/6 Sm 1/6 Eu 1/6 Gd 1/6 M 1/6 ) 2 Sn 2 O 7 (M = Dy, Ho, Er, or Yb) pyrochlore thermistor ceramics for 1500 ° C applications

In this research, a series of rare-earth stannate ceramics (La 1/6 Nd 1/6 Sm 1/6 Eu 1/6 Gd 1/6 M 1/6 ) 2 Sn 2 O 7 (M = Dy, Ho, Er, or Yb) were synthesized using the high-temperature solid-state method for potential applications in high- temperature thermistors. Analyses via X-ray diffraction, Raman spectroscopy, and energy dispersive spectroscopy confirmed that all samples possessed a pyrochlore structure with high-entropy characteristics. Electrical analysis demonstrated that these samples exhibited high resistivity at elevated temperatures and a linear relationship between the logarithm of resistivity and the inverse of temperature. These properties render them suitable as thermistors for applications across a broad temperature range from 600 to 1500 degrees C. Ab initio molecular dynamics simulations revealed that, due to their excellent structural stability even at temperatures up to 1500 degrees C, these ceramics exhibited aging stability at this temperature, with a minimal resistance drift rate of only 0.816 % after a 500h aging test. Owing to these characteristics, the (La 1/6 Nd 1/6 Sm 1/6 Eu 1/6 Gd 1/6 M 1/6 ) 2 Sn 2 O 7 (M = Dy, Ho, Er, or Yb) high-entropy ceramics have the potential to be developed into a series of low-cost high- temperature thermistors capable of operating at temperatures up to 1500 degrees C.