Temperature sensing array utilizing the metal to insulator transition of Nd_xSm_1-xNiO₃

The rare-earth nickelates (ReNiO₃) exhibit widely tunable metal-to-insulator transition (MIT) properties with negligible variations in lattice constants and small latent heat across the critical temperature (T_MIT). In particular, it is worth noticing that compared to the more commonly investigated vanadium oxides, the MIT of ReNiO₃ is less abrupt but is usually across wider range of temperature. This sheds a light on their alternative applications as negative temperature coefficient resistance (NTCR) thermistors with high sensitivity compared to the existing NTCR thermistor, other than their expected usage as critical temperature resistance (CTR) thermistors. Herein, we demonstrate the NTCR thermistor functionality for using the adjustable MIT of Nd_xSm_1-xNiO₃ within 200-400 K that shows larger magnitudes of NTCR (e.g., more than 7 %/K) that is unachievable in conventional NTCR thermistor materials. The temperature dependence of resistance (R-T) shows sharp variation during the MIT of Nd_xSm_1-xNiO₃ across a temperature range of 200-400 K with no hysteresis via decreasing the content of Nd (e.g., 0<x<0.2), and such ρ-T tendency can be linearized by introducing optimum parallel resistor. The sensitive range of temperature can be further extended to 210-360 K, via combining a series of Nd_xSm_1-xNiO₃ with 8 rare-earth co-occupation ratios and T_MIT as an array, with high magnitude of NTCR (e.g., 7-14 %/K) covering the entire range of temperature.