Entropy-mediated stable structural evolution of (HoErTmYbLu)0.2TaO4 for high-temperature thermosensitive applications

Abstract

The structural stability and electrical stability of thermosensitive ceramics are critical to their use under high-temperature conditions. Nevertheless, achieving concurrent stabilization of crystallographic configurations and electrical characteristics at elevated temperatures remains a persistent challenge for rare earth tantalite thermosensitive ceramics. Herein, we propose a high-entropy strategy to design “localized alternating tension strain” by introducing a large number of different kinds of [REO₈] in combination with the original distortion [TaO₆] to stabilize the electrical properties of the rare earth tantalite material. The obtained (HoErTmYbLu)_0.2TaO₄ material demonstrates an intriguing self-compensation mechanism wherein the lattice distortion induced by the high-entropy configuration effectively counteracts inherent structural distortions arising from interconnected [TaO₆] octahedral units. This synergistic distortion compensation engenders exceptional stability, as evidenced by a remarkably low relative standard deviation (RSD) of 0.0311 in resistance during 180 s continuous measurements. The material exhibits high temperature measurement sensitivity (B = 12 851 K) and superior thermoresistive consistency across an ultra-wide temperature range (673–1773 K), with resistivity–temperature dependence closely adhering to the Arrhenius equation (Pearson's r = 0.99819). After aging for 50 h, the aging coefficient begins to stabilize and only fluctuates within 3%. This investigation establishes a paradigm for developing high-performance thermosensitive ceramics through entropy-mediated structural stabilization.