Research Projects

In the past few years, High Entropy Materials (HEMs) have garnered huge attention due to their unique functional properties. These are the special class of materials where single Wyckoff lattice site is populated with 5 major elements in an equiatomic ratio with ΔSconfig ≥ 1.61 R. These materials are crystalized in single phase structure, driven by the entropy stabilization. Among HEMs, high entropy oxides have been largely investigated and particularly the HE-perovskite oxides (5A0.2)Mn/Co/FeO3, Ln(5TM0.2)O3 (A= rare earth, alkaline earth and TM= transition metal ions) are the famous examples for their multifunctional properties. On the hand, halide perovskite has been emerged as a promising class of materials due to their exciting optoelectronic properties. Importantly, halide perovskite the dimensionality is determined by the number of spatial directions in which the [BX6]4− octahedra are connected, can range from 3D to 2D to 1D and 0D configurations.[6] Recently, low dimensional double halide perovskites of heavy TM ions like MA2NaIRuIIICl6, MA2NaIMoIIICl6, (C6H5CH2NH3)2RuCl6, (C6H5C2H4NH3)2MoCl4 has been explored with some exciting magnetic properties including investigation of spin orbit coupling strength and also for 2D magnetism. These double perovskites have ordered structure but there are few example of multimetallic halide perovskites have disordered structure meaning the metals are occupying in same crystallographic site. As per our knowledge there is a limited number of metals we can put in the lattice site. Now our goal is to explore double halide perovskites containing multiple elements, more practically, with the high entropy approach. It is worth mentioning that the high entropy approach to the halide perovskites is the previously unexplored route to tailor their magnetic properties. The HE-approach offers a novel strategy to engineer halide perovskites by incorporating multiple cations which results in exotic properties. In HE-halide perovskite, the population of multiple elements in the A-site can appear large lattice distortion in crystal structure which can be highly influences the magnetic property of that system by fine tuning of bond angle and bond length parameters. Importantly, the HE-approaches offer to incorporate multiple transition metal cations with variable oxidation state which appears multiple and complex magnetic exchange interaction in the system and may be results in a very distinct magnetic behaviour apart from their conventional counterpart and emerges with new magnetic phenomenon. The HE-approach offers to leverage exaggerated chemical disordering which may be exploited to generate tunable magnetic behaviour from magnetically frustrated state or spin glass state to long range ordered state. The investigation on the magnetic properties of high entropy halide perovskites (HEHPs) is not explored yet. Hence, it will be worth investigating the magnetism of HEHPs systems.

High Entropy, Disordering, Halide Perovskite, Hybrid Halide Perovskite, Magnetism, Phase Change Materials