Sr2IrO4 was predicted to be a high temperature superconductor upon electron doping since it highly resembles the cuprates in crystal structure, electronic structure and magnetic coupling constants. Here we report scanning tunneling microscopy/spectroscopy (STM/STS) study of with surface by depositing potassium (K) atoms. At 0.5-0.7 monolayer (ML) K coverage, observed sharp, V-shaped gap about 95% loss density state (DOS) at EFand visible coherence peaks. The magnitude is 25-30 meV for...

Abstract The magnetocaloric effect (MCE) is described by the change in temperature of a material magnetic field variation and crucial subject magnetism; it motivated desire to enhance energy-efficient refrigeration for clean technology. Despite recent discovery giant cryogenic MCE double perovskites, role anisotropy has not yet been clearly discussed, because averaging polycrystalline samples. Here, we investigated anisotropic single-crystal perovskite Gd 2 CoMnO 6 . In addition...

We investigated the anisotropy of magnetic and magnetocaloric properties single-crystalline double-perovskite $\mathrm{T}{\mathrm{b}}_{2}\mathrm{CoMn}{\mathrm{O}}_{6}$, which crystallizes in a monoclinic $P{2}_{1}/n$ structure. Due to dissimilar anisotropy, ferromagnetic order $\mathrm{C}{\mathrm{o}}^{2+}$ $\mathrm{M}{\mathrm{n}}^{4+}$ moments emerges along $c$ axis at ${T}_{\mathrm{C}}=100\phantom{\rule{0.16em}{0ex}}\mathrm{K}$, larger $\mathrm{T}{\mathrm{b}}^{3+}$ align perpendicular axis,...

We have successfully synthesized the series of double-perovskite R2CoMnO6 (R = rare earth: La to Lu) single crystals and investigated their magnetic properties. The ferromagnetic order Co(2+)/Mn(4+) spins emerges mainly along c axis. Upon decreasing size earth ion, transition temperature decreases linearly from 204 K for La2CoMnO6 48 Lu2CoMnO6, with enhancement monoclinic distortion. magnetic-field dependences magnetization reveal various characteristics such as metamagnetic in R Eu,...

Polarons are prevalent in condensed matter systems with strong electron-phonon coupling. The adiabaticity of the polaron relates to its transport properties and spatial extent. To date, only adiabatic small formation has been measured following photoexcitation. lattice reorganization energy is large enough that first electron-optical phonon scattering event creates a without requiring substantial carrier thermalization. We measure frustrating iron-centered octahedra rare-earth orthoferrite ErFeO

We report electric polarization and magnetization measurements in single crystals of double perovskite Lu2MnCoO6 using pulsed magnetic fields optical second harmonic generation (SHG) DC fields. we observe well-resolved field-induced changes the thereby resolve question about whether multiferroic behavior is intrinsic to these materials or an extrinsic feature polycrystals. find along crystalline b-axis, that suppressed by applying a c-axis advance model for origin magnetoelectric coupling....

We have grown single crystals of multiferroic double-perovskite Lu2CoMnO6 and studied the directional dependence their magnetic dielectric properties. The ferromagnetic order emerges below TC ~ 48K along crystallographic c axis. Dielectric anomaly arises b axis at TC, contrary to polycrystalline work suggesting ferroelectricity Through strongly coupled states, highly non-linear variation both constant magnetization was achieved in application fields. This concurrent tunability provides an...

Raman scattering is employed to explore the effects of hole doping in single crystals ${\text{Sr}}_{2}$${\text{Ir}}_{1\ensuremath{-}x}$${\text{Ru}}_{x}$${\text{O}}_{4}$ ($x=0$, 0.01, 0.03, 0.05, 0.1, and 0.2). Introducing a few percentages holes has strong impact on magnetic excitations lattice dynamics. With increasing $x$ well structured two-magnon continuum turns into diffusive scattering. Furthermore one- two-phonon scatterings are rapidly suppressed. Remarkably, two Ir(Ru)-O-Ir(Ru) bond...

Magnetic and dielectric properties of the double perovskite Gd2NiMnO6 were investigated. Ferromagnetic order alternating Ni2+ Mn4+ spins arises below K an additional Gd3+ occurs at K. The formation short-range ferromagnetic clusters accompanied by a Griffiths phase-like feature is also suggested. Under low enough loss temperature regime excluding influence extrinsic effect, highly nonlinear variation constant was achieved in application magnetic fields. Our finding offers efficient approach...

Abstract Exploring new magnetic materials is essential for finding advantageous functional properties such as magnetoresistance, magnetocaloric effect, spintronic functionality, and multiferroicity. Versatile classes of double perovskite compounds have been recently investigated because intriguing physical arising from the proper combination several ions. In this study, it observed that dominant ferrimagnetic phase coexisted with a minor multiferroic in single-crystalline double-perovskite...

Abstract A helimagnet comprises a noncollinear spin structure formed by competing exchange interactions. Recent advances in antiferromagnet-based functionalities have broadened the scope of target materials to include antiferromagnets. However, microscopic understanding magnetic anisotropy associated with intricate evolution states has not yet been accomplished. Here, we explored anisotropic aspects layered EuCo 2 As measuring field and angle dependence torque. By adopting an easy-plane...

In order to explore the consequences of spin-orbit coupling on spin-phonon interactions in a set chemically-similar mixed metal oxides, we measured infrared vibrational properties Co$_4B_2$O$_9$ ($B$ = Nb, Ta) as function temperature and compared our findings with lattice dynamics calculations several different models coupling. Frequency vs. trends for Co$^{2+}$ shearing mode near 150 cm$^{-1}$ reveal significant shifts across magnetic ordering that are especially large relative terms....

Magnetic anisotropy in strontium iridate ($\mathrm{S}{\mathrm{r}}_{2}\mathrm{Ir}{\mathrm{O}}_{4}$) is found to be large because of the strong spin-orbit interactions. In our work, we studied in-plane magnetic $\mathrm{S}{\mathrm{r}}_{2}\mathrm{Ir}{\mathrm{O}}_{4}$ and traced anisotropic exchange interactions between isospins crystal. The magnetic-field--dependent torque \ensuremath{\tau}($H$) showed a prominent transition from canted antiferromagnetic state weak ferromagnetic (WFM) state. A...

Although abundant research has focused recently on the quantum criticality of itinerant magnets, critical phenomena insulating magnets in vicinity endpoints (CEP's) have rarely been revealed. Here we observe an emergent CEP at 2.05 T and 2.2 K with a suppressed thermal conductivity concomitant strong fluctuations evident via divergent magnetic susceptibility (e.g., χ''(2.05 T,2.2 K)/χ''(3 K)≈23,500%, comparable to opalescence water) hexagonal antiferromagnet HoMnO3.

We report the discovery of finite length scale effects on vibronic coupling in nanoscale α-Fe2O3 as measured by behavior vibronically activated d-d on-site excitations Fe3+ a function size and shape. An oscillator strength analysis reveals that frequency coupled symmetry-breaking phonon changes with size, crossover we analyze terms increasing three-dimensional character to displacement pattern. These findings demonstrate flexibility mixing processes confined systems suggest strategy for both...

Abstract Emerging from competing exchange interactions, the helimagnetic order describes a noncollinear spin texture of antiferromagnets. Although collinear antiferromagnets act as elemental building blocks antiferromagnetic (AFM) spintronics, until now, potential implementing spintronic functionality in has not been clarified. Here, we propose an AFM helimagnet EuCo 2 As novel single-phase material that exhibits remarkable sign reversal anisotropic magnetoresistance (AMR). The contrast AMR...

We have investigated the influence of different annealing conditions on magnetic properties single crystals double‐perovskite Y 2 CoMnO 6 . The ferromagnetic moment along c ‐axis with large coercivity and high squareness ratio was observed. Particularly, in quenched specimen, functionality has been greatly improved compared to that as‐grown crystal. maximum energy product increased by ∼120% ∼50%, respectively, comprising substantial disorders defects. Our result renders an efficient route...

Abstract The influence of magnetocrystalline anisotropy (MCA) on antiferromagnetism is elucidated through the characterization spin‒flop transition. However, due to a lack suitable candidates for investigation, detailed understanding preservation transition in presence low MCA energy remains elusive. In this study, we introduce CrPS 4 , which two-dimensional van der Waals antiferromagnet, as an ideal system explore exceedingly weak limit thermally-evolved energy. By employing uniaxially...

We measure how coherent charge hopping competes with and slows small polaron formation. The coupling of photoexcited carriers phonons in the crystal lattice that results formation causes carrier localization limits transport to site-to-site hopping. ErFeO 3 , a rare-earth orthoferrite, is designed where large rare earth atom frustrates FeO 6 octahedra, reducing energetic favorability compare transient extreme ultraviolet (XUV) measurements ab initio theory quantify rate mobility. Polaron...

Controlling the effects of photoexcited polarons in transition metal oxides can enable long timescale charge separation necessary for renewable energy applications as well controlling new quantum phases through dynamically tunable electron-phonon coupling. In previously studied oxides, polaron formation is facilitated by a ligand-to-metal transfer (LMCT). When formed, oxygen atoms move away from iron centers, which increases carrier localization at center and decreases hopping. Studies...

Abstract Explorations of van der Waals (vdW) antiferromagnets have revealed new avenues for understanding the fundamentals highly anisotropic magnetism and realizing spin-based functional properties. However, there is a serious limitation to feasibility spintronic applications at room temperature owing lack suitable materials. In this work, we examined magnetic characteristics Co-doped Fe 5 GeTe 2 , high- T N antiferromagnet with = 350 K in which multilayers are intrinsically formed. Our...