Homogenizing energy landscapes and microstructure enabling a linear and stable thermal sensing response in high-entropy niobates

• • The HEN-0.2Mo ceramic achieves an Arrhenius linearity of R² = 0.99907 across −50 to 1250 °C with a B-value fluctuation of only 4.44%, directly enabling calibration-free NTC thermistor operation in hypersonic engine monitoring where conventional spinels fail above 300 °C due to exponential drift. • • Grain and grain-boundary activation energies are nearly identical (Eg = 1.209 eV, Egb = 1.218 eV; ΔEa = 0.009 eV), eliminating the space-charge-induced nonlinearity that plagues polycrystalline NTC ceramics and ensuring stable response under thermal cycling. • • After 1000 h aging at 1250 °C, the stabilized-stage resistance drift is only 1.09%, a tenfold improvement over typical spinel-based sensors, which translates to reduced recalibration intervals and lower maintenance costs in aerospace and industrial furnace applications. • • Mo doping at x = 0.2 preserves the monoclinic ferroelastic framework while broadening local cation-distance distributions and increasing displacement amplitudes, providing a scalable compositional lever for tuning transport properties without sacrificing phase stability.