오윤석 교수

Selenium substitution drastically increases the transition temperature of iridium ditelluride (IrTe(2)) to a diamagnetic superstructure from 278 to 560 K. Transmission electron microscopy experiments revealed that this enhancement is accompanied by the evolution of nonsinusoidal structure modulations from q = 1/5(101) to q = 1/6(101) types. These comprehensive results are consistent with the concept of the destabilization of polymeric Te-Te bonds at the transition, the temperature of which is in

Temperature- and field-dependent measurements of the Hall effect of pure and 4% Rh-doped URu2Si2 reveal low density (0.03 hole/U) high mobility carriers to be unique to the "hidden order" phase and consistent with an itinerant density-wave order parameter. The Fermi surface undergoes a series of abrupt changes as the magnetic field is increased. When combined with existing de Haas-van Alphen data, the Hall data expose a strong interplay between the stability of the "hidden order," the degree of

Abstract Interaction between dipoles often emerges intriguing physical phenomena, such as exchange bias in the magnetic heterostructures and magnetoelectric effect in multiferroics, which lead to advances in multifunctional heterostructures. However, the defect‐dipole tends to be considered the undesired to deteriorate the electronic functionality. Here, deterministic switching between the ferroelectric and the pinched states by exploiting a new substrate of cubic perovskite, BaZrO 3 is reported

Abstract Growth and characterization of metal‐oxide thin films foster successful development of oxide‐material‐integrated thin‐film devices represented by metal‐oxide‐semiconductor field‐effect transistors (MOSFET), drawing enormous technological and scientific interest for several decades. In recent years, functional oxide heterostructures have demonstrated remarkable achievements in modern technologies and provided deeper insights into condensed‐matter physics and materials science owing to th

Comparative studies of magnetoelectric susceptibility ($\ensuremath{\alpha}$), magnetization ($M$), and magnetostriction ($u$) in TbMn${}_{2}$O${}_{5}$ reveal that the increment of $M$ owing to the field-induced Tb${}^{3+}$ spin alignment produces a field-asymmetric line shape in the $\ensuremath{\alpha}(H)$ curve, which is conspicuous in a low-temperature incommensurate phase but persistently subsists in the entire ferroelectric phase. Correlations among electric polarization, $u$, and ${M}^{2}

The structure of dielectric perovskite BaZrO3, long known to be cubic at room temperature without any structural phase transition with variation in temperature, has been recently disputed to have different ground state structures with lower symmetries involving octahedra rotation. Pressure-dependent Raman scattering measurements can identify the hierarchy of energetically-adjacent polymorphs, helping in turn to understand its ground state structure at atmospheric pressure. Here, the Raman scatte

This mini-review emphasizes the potential of biomass-derived materials as sustainable components for next-generation electrochemical energy storage systems. Biomass obtained from abundant and renewable natural resources can be transformed into carbonaceous materials. These materials typically possess hierarchical porosities, adjustable surface functionalities, and inherent heteroatom doping. These physical and chemical characteristics provide the structural and chemical flexibility needed for va

Lithium-ion batteries (LIBs) have reached their theoretical capacity limits and face significant challenges in meeting the energy density requirements for large-scale applications such as electric vehicles and energy storage systems. Lithium-sulfur batteries (LSBs) are considered promising candidates for replacing LIBs owing to their high theoretical capacity and energy density. However, despite these advantages, the commercialization of LSBs remains challenging owing to critical issues, such as

Abstract:\n\nNamed after Russian mineralogist L. Perovski, Perovskite is material which has the chemical formula ABX3 (A and B are cations, and X is an anion) and a crystal structure with the anion X in the face centers. The Perovskite compounds exhibit a variety of exotic physical phenomena, such as high-Tc superconductivity as well as quantum criticality, heavy fermion, multiferroics, morphotropic phase boundary. In terms of new functional material design, the Perovskite has high tunability. I