High Entropy Approach to Engineer Strongly Correlated Functionalities in Manganites. Issue 2 (30th November 2022)

• Record Type: Journal Article
• Authors: Sarkar, Abhishek; Wang, Di; Kante, Mohana V.; Eiselt, Luis; Trouillet, Vanessa; Iankevich, Gleb; Zhao, Zhibo; Bhattacharya, Subramshu S.; Hahn, Horst; Kruk, Robert
• Is Part Of: Advanced materials. Volume 35:Issue 2(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-11-30
• Subjects: colossal magnetoresistance -- high entropy oxides -- magneto‐electronic phase separation -- metal‐insulator transitions -- strongly correlated electron systems; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.202207436
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: Technologically relevant strongly correlated phenomena such as colossal magnetoresistance (CMR) and metal‐insulator transitions (MIT) exhibited by perovskite manganites are driven and enhanced by the coexistence of multiple competing magneto‐electronic phases. Such magneto‐electronic inhomogeneity is governed by the intrinsic lattice‐charge‐spin‐orbital correlations, which, in turn, are conventionally tailored in manganites via chemical substitution, charge doping, or strain engineering. Alternately, the recently discovered high entropy oxides (HEOs), owing to the presence of multiple‐principal cations on a given sub‐lattice, exhibit indications of an inherent magneto‐electronic phase separation encapsulated in a single crystallographic phase. Here, the high entropy (HE) concept is combined with standard property control by hole doping in a series of single‐phase orthorhombic HE‐manganites (HE‐Mn), (Gd0.25 La0.25 Nd0.25 Sm0.25 )1‐ x Sr x MnO3 ( x = 0–0.5). High‐resolution transmission microscopy reveals hitherto‐unknown lattice imperfections in HEOs: twins, stacking faults, and missing planes. Magnetometry and electrical measurements infer three distinct ground states—insulating antiferromagnetic, unpercolated metallic ferromagnetic, and long‐range metallic ferromagnetic—coexisting or/and competing as a result of hole doping and multi‐cation complexity. Consequently, CMR ≈1550% stemming from an MIT is observed in polycrystalline pellets, matching the best‐known values for bulk conventional manganites. Hence, this initial case study highlights the potential for a synergetic development of strongly correlated oxides offered by the high entropy design approach. Abstract : The study introduces a new approach to materials design based on the inherent magneto‐electronic inhomogeneities present in high entropy (HE) materials to manipulate and enhance strongly correlated functionalities in oxide systems. In this case study, substantial degree of colossal magnetoresistance (CMR) and unique lattice imperfections are observed in charge‐doped HE‐manganites.