Nonlinearity in regulating the metal to insulator transition of ReNiO3 towards low temperature range. Issue 21 (1st November 2022) - Li, Xiaoyu
Abstract: Among the existing material family of the correlated oxides, the rare earth nickelates ( Re NiO3 ) exhibit broadly adjustable metal to insulator transition (MIT) properties that enables correlated electronic applications, such as thermistors, thermochromics, and logical devices. Nevertheless, how to accurately control the critical temperature ( T MIT ) of Re NiO3 via the co-occupation of the rare-earth elements is yet worthy to be further explored. Herein, we demonstrate the non-linearity in adjusting the T MIT of Re NiO3 towards lower temperatures via introducing Pr co-occupation within Re NiO3 (e.g., Prx Nd1-x NiO3 and Prx Sm1-x NiO3 ) as synthesized by KCl molten-salt assisted high oxygen pressure reaction approach. Although the T MIT is effectively reduced via Pr substitution, it does not strictly follow a linear relationship, in particular, when there is large difference in the ionic radius of the co-occupation rare-earth elements. Furthermore, the most significant deviation in T MIT from the expected linear relationship appears at an equal co-occupation ratio of the two different rare-earth elements, while the abruption in the variation of resistivity across T MIT is also reduced. The present work highlights the importance to use adjacent rare-earth elements with co-occupation ratio away from 1:1 for achieving more linear adjustment in designing the metal to insulator transition properties for Re NiO3 .