Magnetoelectric effect in multiferroic nickelate perovskite YNiO.

The interaction of magnetic order and spontaneous polarization is a fundamental coupling with the prospect for the control of electronic properties and magnetism. The connection among magnetic order, charge localization and associated metal-insulator transition (MIT) are cornerstones for materials control. Materials that combine both effects are therefore of great interest for testing models that claim the occurrence of spontaneous polarization from magnetic and charge order.

Non-equilibrium dynamics of spin-lattice coupling.

Quantifying the dynamics of normal modes and how they interact with other excitations is of central importance in condensed matter. Spin-lattice coupling is relevant to several sub-fields of condensed matter physics; examples include spintronics, high-T superconductivity, and topological materials. However, experimental approaches that can directly measure it are rare and incomplete.

Combined Theoretical and Experimental Study of the Moiré Dislocation Network at the SrTiO-(La,Sr)(Al,Ta)O Interface.

Recently, a highly ordered Moiré dislocation lattice was identified at the interface between a SrTiO (STO) thin film and the (LaAlO)(SrTaAlO) (LSAT) substrate. A fundamental understanding of the local ionic and electronic structures around the dislocation cores is crucial to further engineer the properties of these complex multifunctional heterostructures. Here, we combine experimental characterization via analytical scanning transmission electron microscopy with results of molecular dynamics and density functional theory calculations to gain insights into the structure and defect chemistry of these dislocation arrays.

Designing Magnetism in High Entropy Oxides.

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 are lacking. Here, it is demonstrated that high entropy oxides present a previously unexplored route to designing materials in which the presence of strong local compositional disorder may be exploited to generate tunable magnetic behaviors-from macroscopically ordered states to frustration-driven dynamic spin interactions. Single-crystal La(Cr Mn Fe Co Ni )O films are used as a model system hosting a magnetic sublattice with a high degree of microstate disorder in the form of site-to-site spin and exchange type inhomogeneity.

Correlated oxide Dirac semimetal in the extreme quantum limit.

Quantum materials (QMs) with strong correlation and nontrivial topology are indispensable to next-generation information and computing technologies. Exploitation of topological band structure is an ideal starting point to realize correlated topological QMs. Here, we report that strain-induced symmetry modification in correlated oxide SrNbO thin films creates an emerging topological band structure.

Strain-driven autonomous control of cation distribution for artificial ferroelectrics.

In past few decades, there have been substantial advances in theoretical material design and experimental synthesis, which play a key role in the steep ascent of developing functional materials with unprecedented properties useful for next-generation technologies. However, the ultimate goal of synthesis science, i.e.

Magnetic Texture in Insulating Single Crystal High Entropy Oxide Spinel Films.

Magnetic insulators are important materials for a range of next-generation memory and spintronic applications. Structural constraints in this class of devices generally require a clean heterointerface that allows effective magnetic coupling between the insulating layer and the conducting layer. However, there are relatively few examples of magnetic insulators that can be synthesized with surface qualities that would allow these smooth interfaces and precisely tuned interfacial magnetic exchange coupling, which might be applicable at room temperature.

Epitaxial Stabilization of Single-Crystal Multiferroic YCrO Thin Films.

We report on the growth of stoichiometric, single-crystal YCrO epitaxial thin films on (001) SrTiO substrates using pulsed laser deposition. X-ray diffraction and atomic force microscopy reveal that the films grew in a layer-by-layer fashion with excellent crystallinity and atomically smooth surfaces. Magnetization measurements demonstrate that the material is ferromagnetic below 144 K.

Applying Configurational Complexity to the 2D Ruddlesden-Popper Crystal Structure.

The layered Ruddlesden-Popper crystal structure can host a broad range of functionally important behaviors. Here we establish extraordinary configurational disorder in a layered Ruddlesden-Popper (RP) structure using entropy stabilization assisted synthesis. A protype CuO RP cuprate oxide with five cations on the -site sublattice is designed and fabricated into epitaxial single crystal films using pulsed laser deposition.

Interfacial tuning of chiral magnetic interactions for large topological Hall effects in LaMnO/SrIrO heterostructures.

Chiral interactions in magnetic systems can give rise to rich physics manifested, for example, as nontrivial spin textures. The foremost interaction responsible for chiral magnetism is the Dzyaloshinskii-Moriya interaction (DMI), resulting from inversion symmetry breaking in the presence of strong spin-orbit coupling. However, the atomistic origin of DMIs and their relationship to emergent electrodynamic phenomena, such as topological Hall effect (THE), remain unclear.

Large orbital polarization in nickelate-cuprate heterostructures by dimensional control of oxygen coordination.

Artificial heterostructures composed of dissimilar transition metal oxides provide unprecedented opportunities to create remarkable physical phenomena. Here, we report a means to deliberately control the orbital polarization in LaNiO (LNO) through interfacing with SrCuO (SCO), which has an infinite-layer structure for CuO. Dimensional control of SCO results in a planar-type (P-SCO) to chain-type (C-SCO) structure transition depending on the SCO thickness.

Room-Temperature Ferromagnetic Insulating State in Cation-Ordered Double-Perovskite Sr Fe Re O Films.

Ferromagnetic insulators (FMIs) are one of the most important components in developing dissipationless electronic and spintronic devices. However, FMIs are innately rare to find in nature as ferromagnetism generally accompanies metallicity. Here, novel room-temperature FMI films that are epitaxially synthesized by deliberate control of the ratio between two B-site cations in the double perovskite Sr Fe Re O (-0.

Spin canting across core/shell FeO/MnFeO nanoparticles.

Magnetic nanoparticles (MNPs) have become increasingly important in biomedical applications like magnetic imaging and hyperthermia based cancer treatment. Understanding their magnetic spin configurations is important for optimizing these applications. The measured magnetization of MNPs can be significantly lower than bulk counterparts, often due to canted spins.