Yufan Shen 교수

Cation distribution in transition-metal oxides is closely tied to their physical properties. Here we employed resonant x-ray-diffraction technique and quantitatively evaluated the cation distribution in inverse spinel $\mathrm{NiC}{\mathrm{o}}_{2}{\mathrm{O}}_{4}$ films that were epitaxially grown by pulsed laser deposition. Our results reveal that oxygen partial pressure during growth ${P}_{\mathrm{O}2}$ is a key parameter determining cation distribution in the films, with a larger ${P}_{\mathr

Spin polarization and magnetic anisotropy are key properties that determine the performance of magnetic tunnel junctions (MTJs), which are utilized in various spintronic devices. Although materials that have both high spin polarization and sufficient perpendicular magnetic anisotropy are desirable for further developments of MTJs, such materials are rare because electronic structures necessary for achieving these two properties are distinct. Here, we experimentally show the inverse spinel ferrim

Two-dimensional freestanding membranes of materials, which can be transferred onto and make interfaces with any material, have attracted attention in the search for functional properties that can be utilized for next-generation nanoscale devices. We fabricated stable 1-nm-thick hafnia membranes exhibiting the metastable rhombohedral structure and out-of-plane ferroelectric polarizations as large as 13 μC/cm². We also found that the rhombohedral phase transforms into another metastable

The binary fluorite oxide ${\mathrm{Hf}}_{0.5}{\mathrm{Zr}}_{0.5}{\mathrm{O}}_{2}$ tends to grab a significant amount of notice due to the distinct and superior ferroelectricity found in its metastable phase. Stabilizing the metastable ferroelectric phase and delineating the underlying growth mechanism, however, are still challenging. Recent discoveries of metastable ferroelectric ${\mathrm{Hf}}_{0.5}{\mathrm{Zr}}_{0.5}{\mathrm{O}}_{2}$ epitaxially grown on structurally dissimilar perovskite oxi

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Abstract Electrochemical protonation, which can be realized in an electric-field-effect transistor with a gate layer consisting of a proton-conducting electrolyte Nafion membrane, offers a simple way of electrically tuning the physical properties of materials. In this study, we grew (010)-oriented epitaxial films of brownmillerite-structured SrCoO 2.5 on various substrates whose lattice mismatch against SCO ranged from 0% to −2.9% by pulsed laser deposition and investigated the effect of substra

Fabricating and investigating freestanding membranes of materials are key approaches for exploring the intrinsic properties of those materials, even in their metastable phases stabilized by external factors. In this study, we fabricated freestanding $\mathrm{Zr}{\mathrm{O}}_{2}$ membranes with metastable crystal structures by exfoliating $\mathrm{Zr}{\mathrm{O}}_{2}$ (ZO) epitaxial layers from $\mathrm{Zr}{\mathrm{O}}_{2}/\mathrm{L}{\mathrm{a}}_{0.7}\mathrm{S}{\mathrm{r}}_{0.3}\mathrm{Mn}{\mathr

While oxide heterostructures with emergent properties have garnered a great amount of research interest, heterostructures consisting of oxides with metastable phases have barely been investigated. Here, we fabricated epitaxial bilayer structures based on ZrO2 (ZO) and Hf0.5Zr0.5O2 (HZO) whose single layers, respectively, possess non-polar and polar metastable structures and investigated their structural and ferroelectric properties. We found that the ZO/HZO heterostructures exhibit ferroelectric

The structural versatility and environment friendly characters of nitride phosphors make it possible to attain all the emission colors from blue to red and are good candidate for warm white LEDs. Eu2+doped Sr Si O3-Sr Si2O2N2-Sr2Si5N8 phosphors were prepared by carbothermol reduction and nitridation( CRN) method.Phase composition in the final product was confirmed by X-ray diffractometer( XRD). Fluorospectro photometer was used to measure the photoluminescence( PL) spectrum and the results showe

The binary fluorite oxide Hf0.5Zr0.5O2 tends to grab a significant amount of notice due to the distinct and superior ferroelectricity found in its metastable phase. Stabilizing the metastable ferroelectric phase and delineating the underlying growth mechanism, however, are still challenging. Recent discoveries of metastable ferroelectric Hf0.5Zr0.5O2 epitaxially grown on structurally dissimilar perovskite oxides have triggered intensive investigations on the ferroelectricity in materials that ar