Temperature-tunable multiple dielectric switch in hybrid rare-earth perovskites regulated by hierarchical guest dynamics, lanthanide contraction and doping

Abstract

Dielectric switches play an important role in electrical and electronic devices. Here we report a unique class of cage-like hybrid rare-earth perovskites, (i-PrNHMe₂)₂[RbLn(NO₃)₆] (Ln = La, Ce, Nd or Sm), capable of functioning as temperature-responsive multiple dielectric switches. The strategic incorporation of a conformationally flexible sphere-like guest (i-PrNHMe₂)⁺ cation into the cage-like perovskite framework is in favor of the occurrence of hierarchical guest dynamics accompanied by stepwise phase transitions, leading to seldom observed multiple dielectric switching of “Low ↔ High ↔ Low ↔ High” upon heating. Furthermore, the utilizing of lanthanide contraction or rare-earth doping allows for fine tuning of the switching temperature. In addition, multiaxial ferroelasticity is found in these perovskites. Overall, this study provides a good approach for the design of temperature-tunable multiple dielectric switches.