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Updated: Aug 21, 2025
08:45
Fabrication of Spatially Confined Complex Oxides
Published on: July 1, 2013
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High Entropy Approach to Engineer Strongly Correlated Functionalities in Manganites
Abhishek Sarkar1,2, Di Wang2,3, Mohana V Kante2
1KIT-TUD Joint Research Laboratory Nanomaterials - Technische Universität Darmstadt, Otto-Berndt-Str. 3, 64287, Darmstadt, Germany.
Advanced Materials (Deerfield Beach, Fla.)
|November 16, 2022
Summary
High entropy manganites exhibit colossal magnetoresistance (CMR) and metal-insulator transitions (MIT) due to competing magnetic phases. This novel approach offers a new pathway for developing advanced strongly correlated oxides.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Solid State Chemistry
Background:
- Perovskite manganites display technologically relevant phenomena like colossal magnetoresistance (CMR) and metal-insulator transitions (MIT).
- These properties arise from competing magneto-electronic phases governed by lattice-charge-spin-orbital correlations.
- Conventional methods to tailor these properties include chemical substitution, charge doping, and strain engineering.
Purpose of the Study:
- To investigate the potential of high entropy oxides (HEOs) in hosting and controlling magneto-electronic phase separation within a single crystallographic phase.
- To combine the high entropy concept with hole doping in a series of single-phase orthorhombic high entropy manganites (HE-Mn).
- To explore the impact of multi-cation complexity and hole doping on the magnetic and electronic properties of these novel materials.
Main Methods:
- Synthesis of a series of single-phase orthorhombic high entropy manganites (HE-Mn) with varying Sr doping levels: (Gd0.25La0.25Nd0.25Sm0.25)1-x Srx MnO3 (x = 0-0.5).
- High-resolution transmission electron microscopy (HRTEM) to identify lattice imperfections such as twins, stacking faults, and missing planes.
- Magnetometry and electrical transport measurements to probe magnetic ground states and electrical conductivity.
Main Results:
- High-resolution transmission microscopy revealed previously unobserved lattice imperfections in HEOs, including twins, stacking faults, and missing planes.
- Magnetometry and electrical measurements identified three distinct ground states: insulating antiferromagnetic, unpercolated metallic ferromagnetic, and long-range metallic ferromagnetic.
- These states were found to coexist and compete, driven by hole doping and the inherent multi-cation complexity of the HE-manganites.
- Colossal magnetoresistance (CMR) reaching approximately 1550%, associated with a metal-insulator transition (MIT), was observed in polycrystalline pellets.
Conclusions:
- The study demonstrates that the high entropy design approach can intrinsically encapsulate magneto-electronic phase separation within a single crystallographic phase.
- The combination of high entropy and hole doping in HE-manganites leads to complex competing ground states and significant CMR effects.
- This work highlights the potential of high entropy design for the synergetic development of strongly correlated oxides with tailored properties.
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