Designer Magnetism in High Entropy Oxides

Abstract

Disorder can have a dominating influence on correlated and quantum materials leading to novel behaviors which have no clean limit counterparts. In magnetic systems, spin and exchange disorder can provide access to quantum criticality, frustration, and spin dynamics, but broad tunability of these responses and a deeper understanding of strong limit disorder is lacking. In this work, we demonstrate that high entropy oxides present an unexplored route to designing quantum materials in which the presence of strong local compositional disorder hosted on a positionally ordered lattice can be used to generate highly tunable emergent magnetic behavior--from macroscopically ordered states to frustration-driven dynamic spin interactions. Single crystal La(Cr0.2Mn0.2Fe0.2Co0.2Ni0.2)O3 films are used as a structurally uniform model system hosting a magnetic sublattice with massive microstate disorder in the form of site-to-site spin and exchange type inhomogeneity. A classical Heisenberg model is found to be sufficient to describe how compositionally disordered systems can paradoxically host long-range magnetic uniformity and demonstrates that balancing the populating elements based on their discrete quantum parameters can be used to give continuous control over ordering types and critical temperatures. Theory-guided experiments show that composite exchange values derived from the complex mix of microstate interactions can be used to design the required compositional parameters for a desired response. These predicted materials are synthesized and found to possess an incipient quantum critical point when magnetic ordering types are designed to be in direct competition; this leads to highly controllable exchange bias sensitivity in the monolithic single crystal films previously accessible only in intentionally designed bilayer heterojunctions.

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Cited by in corpus (14)

• What is in a Name: Defining -High Entropy- Oxides
• Designer Magnetism in High Entropy Oxides
• High entropy ceramics for applications in extreme environments
• Disorder by Design: Unveiling Local Structure and Functional Insights in High Entropy Oxides
• Local structure maturation in high entropy oxide (Mg,Co,Ni,Cu,Zn)1-x(Cr,Mn)xO thin films
• Order evolution from a high-entropy matrix: understanding and predicting paths to low temperature equilibrium
• Embracing Disorder in Quantum Materials Design
• Hole doping in compositionally complex correlated oxide enables tunable exchange biasing
• Dielectric Properties of Disordered A6B2O17 (A = Zr; B = Nb, Ta) Phases
• Maximizing solubility in rock salt high-entropy oxides
• Extreme disorder in crystalline perovskite oxide: a new paradigm in quantum materials research
• Superconductivity in Compositionally-Complex Cuprates with the YBa${}_2$Cu${}_3$O${}_{7-x}$ Structure
• Anomalous Crystallinity and Magnetism in Chemically Disordered Coherent Heterostructures
• Impact of Stealthy Hyperuniform Magnetic Impurity Configurations on Bulk Magnetism in a Two-dimensional Heisenberg Model