Browse
Submit Data
Databases
API
Help

Dataset Information

25 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Creating Ferromagnetic Insulating La_0.9Ba_0.1MnO₃ Thin Films by Tuning Lateral Coherence Length.

ABSTRACT: In this work, heteroepitaxial vertically aligned nanocomposite (VAN) La_0.9Ba_0.1MnO₃ (LBMO)-CeO₂ films are engineered to produce ferromagnetic insulating (FMI) films. From combined X-ray photoelectron spectroscopy, X-ray diffraction, and electron microscopy, the elimination of the insulator-metal (I-M) transition is shown to result from the creation of very small lateral coherence lengths (with the corresponding lateral size ∼ 3 nm (∼7 u.c.)) in the LBMO matrix, achieved by engineering a high density of CeO₂ nanocolumns in the matrix. The small lateral coherence length leads to a shift in the valence band maximum and reduction of the double exchange (DE) coupling. There is no "dead layer" effect at the smallest achieved lateral coherence length of ∼3 nm. The FMI behavior obtained by lateral dimensional tuning is independent of substrate interactions, thus intrinsic to the film itself and hence not related to film thickness. The unique properties of VAN films give the possibility for multilayer spintronic devices that can be made without interface degradation effects between the layers.

SUBMITTER: Yun C

PROVIDER: S-EPMC8023513 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Ferromagnetic-like behavior of Bi0.9La0.1FeO3-KBr nanocomposites.

Project description:We studied magnetostatic response of the Bi0.9La0.1FeO3- KBr composites (BLFO-KBr) consisting of nanosized (≈100 nm) ferrite Bi0.9La0.1FeO3 (BLFO) conjugated with fine grinded ionic conducting KBr. When the fraction of KBr is rather small (less than 15 wt%) the magnetic response of the composite is very weak and similar to that observed for the BLFO (pure KBr matrix without Bi1-xLaxFeO3 has no magnetic response as anticipated). However, when the fraction of KBr increases above 15%, the magnetic response of the composite changes substantially and the field dependence of magnetization reveals ferromagnetic-like hysteresis loop with a remanent magnetization about 0.14 emu/g and coercive field about 1.8 Tesla (at room temperature). Nothing similar to the ferromagnetic-like hysteresis loop can be observed in Bi1-zLazFeO3 ceramics with z ≤ 0.15, which magnetization quasi-linearly increases with magnetic field. Different physical mechanisms were considered to explain the unusual experimental results for BLFO-KBr nanocomposites, but only those among them, which are highly sensitive to the interaction of antiferromagnetic Bi0.9La0.1FeO3 with ionic conductor KBr, can be relevant.

| S-EPMC6639540 | biostudies-literature

Lu-atom-ordered oxonitridoaluminosilicate Ba0.9Ce0.1LuAl0.2Si3.8N6.9O0.1.

Project description:A single crystal of Ba0.9Ce0.1LuAl0.2Si3.8N6.9O0.1 (barium cerium lutetium aluminosilicate nitride oxide) was obtained by heating a mixed powder of Ba3N2, Si3N4, Al, Lu2O3, and CeO2 at 2173 K for 1 h under N2 gas at 0.85 MPa. X-ray single-crystal structure analysis revealed that the title oxynitride is hexa-gonal (lattice constants: a = 6.0378 (5) Å, c = 9.8133 (9) Å; space group: P63 mc) and isostructural with BaYbSi4N7. (Ba,Ce) and Lu atoms occupy twelvefold and sixfold coordination sites, respectively.

| S-EPMC7643228 | biostudies-literature

Electro-opto-mechano driven reversible multi-state memory devices based on photocurrent in Bi0.9Eu0.1FeO3/La0.67Sr0.33MnO3/PMN-PT heterostructures.

Project description:A single device with extensive new functionality is highly attractive for the increasing demands for complex and multifunctional optoelectronics. Multi-field coupling has been drawing considerable attention because it leads to materials that can be simultaneously operated under several external stimuli (e.g. magnetic field, electric field, electric current, light, strain, etc.), which allows each unit to store multiple bits of information and thus enhance the memory density. In this work, we report an electro-opto-mechano-driven reversible multi-state memory device based on photocurrent in Bi0.9Eu0.1FeO3 (BEFO)/La0.67Sr0.33MnO3 (LSMO)/0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (PMN-PT) heterostructures. It is found that the short-circuit current density (J sc) can be switched by the variation of the potential barrier height and depletion region width at the Pt/BEFO interface modulated by light illumination, external strain, and ferroelectric polarization reversal. This work opens up pathways toward the emergence of novel device design features with dynamic control for developing high-performance electric-optical-mechanism integrated devices based on the BiFeO3-based heterostructures.

| S-EPMC9052503 | biostudies-literature

Observations of Nematicity, Dopants, and Zero-Bias Conductance Peaks for the Ca0.9La0.1FeAs2 Superconductor.

Project description:Ca1-xLaxFeAs2 (CLFA112) belongs to a new family of Fe-based superconductors (FeSCs) and has a unique crystal structure featuring an arsenic zigzag chain layer, which has been proposed to be a possible two-dimensional topological insulator. This suggests that CLFA112 is a potential topological superconductor-a platform to realize Majorana fermions. Up to now, even a clear superconducting (SC) gap in CLFA112 has never been observed, and the SC properties of CLFA112 remain largely elusive. In this letter, we report the results of an atomic-scale investigation of the electronic structure of CLFA112 crystals using low-temperature scanning tunneling microscopy (STM). We revealed four different types of surfaces exhibiting distinct electronic properties, with all surfaces displaying dominating 2 × 1 surface reconstructions. On a Ca/La layer on top of an FeAs layer, a clear SC gap of ~12 mV was observed only at the crevices (vacancies) where the FeAs layer can be directly accessed. Remarkably, the FeAs termination layer displayed a dispersing nematic modulation both in real and q space. We also present peculiar zero-bias conductance peaks for the very As chain layer that is believed to exhibit a topological edge state as well as the influence of La dopants on the As chain layer.

| S-EPMC9962653 | biostudies-literature

Anion Doping of Ferromagnetic Thin Films of La0.74Sr0.26MnO3-? via Topochemical Fluorination.

Project description:Chemical doping via insertion of ions into the lattice of a host material is a key strategy to flexibly manipulate functionalities of materials. In this work, we present a novel case study on the topotactic insertion of fluoride ions into oxygen-deficient ferromagnetic thin films of La0.74Sr0.26MnO3-? (LSMO) epitaxially grown onto single-crystal SrTiO? (STO) substrates. The effect of fluorination on the film structure, composition, and magnetic properties is compared with the case of oxygen-deficient and fully-oxidized LSMO films. Although incorporation of F- anions does not significantly alter the volume of the LSMO unit cell, a strong impact on the magnetic characteristics, including a remarkable suppression of Curie temperature and saturation magnetization accompanied by an increase in magnetic coercivity, was found. The change in magnetic properties can be ascribed to the disruption of the ferromagnetic exchange interactions along Mn-anion-Mn chains driven by F- doping into the LSMO lattice. Our results indicate that F- doping is a powerful means to effectively modify the magnetic functional properties of perovskite manganites.

| S-EPMC6073400 | biostudies-literature

Aliovalent-doped sodium chromium oxide (Na0.9Cr0.9Sn0.1O2 and Na0.8Cr0.9Sb0.1O2) for sodium-ion battery cathodes with high-voltage characteristics.

Project description:NaCrO2 with high rate-capability is an attractive cathode material for sodium-ion batteries (NIBs). However, the amount of reversibly extractable Na+ ions is restricted by half, which results in relatively low energy density for practical NIB cathodes. Herein, we describe aliovalent-doped O3-Na0.9[Cr0.9Sn0.1]O2 (NCSnO) and O3-Na0.8[Cr0.9Sb0.1]O2 (NCSbO), both of which show high-voltage characteristics that translate to an increase in energy density. In contrast to NaCrO2, NCSnO and NCSbO can be reversibly charged to 3.80 and 3.95 V, respectively, delivering 0.5 Na+ along with Cr3+/4+ redox alone. The reversible chargeability to Na0.4[Cr0.9Sn0.1]O2 and Na0.3[Cr0.9Sb0.1]O2 is not associated with the suppression of Cr6+ formation. Both compounds show concentrations of Cr6+ that are higher than that of Na0.3CrO2, with an absence of O3' phases. This implies that aliovalent-doping contributes to a suppression of the Cr6+ migration into tetrahedral sites in the interslab space, which reduces the possibility of irreversible comproportionation. NCSnO and NCSbO deliver capacities comparable to that of NaCrO2, but show a higher average discharge voltage (2.94 V for NaCrO2; 3.14 V for NCSnO; 3.21 V for NCSbO), which leads to a noticeable increase in energy densities. The high-voltage characteristics of NCSnO and NCSbO are also validated via density-functional-theory calculations.

| S-EPMC9058423 | biostudies-literature

Effect of Ba Content on the Activity of La1-x Ba x MnO3 Towards the Oxygen Reduction Reaction.

Project description:The electrocatalytic activity of La1-x Ba x MnO3 nanoparticles towards the oxygen reduction reaction (ORR) is investigated as a function of the A-site composition. Phase-pure oxide nanoparticles with a diameter in the range of 40 to 70 nm were prepared by using an ionic liquid route and deposited onto mesoporous carbon films. The structure and surface composition of the nanoparticles are probed by XRD, TEM, EDX, and XPS. Electrochemical studies carried out under alkaline conditions show a strong correlation between the activity of La1-x Ba x MnO3 and the effective number of reducible Mn sites at the catalysts layer. Our analysis demonstrates that, beyond controlling particle size and surface elemental segregation, understanding and controlling Mn coordination at the first atomic layer is crucial for increasing the performance of these materials.

| S-EPMC6146913 | biostudies-literature

Boosting Upconversion Photoluminescence and Multielectrical Properties via Er-Doping-Modulated Vacancy Control in Ba0.85Ca0.15Ti0.9Zr0.1O3.

Project description:The lead-free 0.5(Ba0.7Ca0.3)TiO3-0.5Ba(Ti0.8Zr0.2)O3 (BCTZ) ceramics with Er doping have shown good upconversion photoluminescence (PL) and desirable optical temperature sensing properties. To bridge a relationship between the structure/intrinsic defects and properties of rare-earth-doped ferroelectrics, we designed and fabricated a series of BCTZ ceramics doped with 1 mol % Er3+ by combining the first-principles calculations and experimental measurements. Theoretically, we discovered that Er can occupy both A sites (i.e., replacing Ba or Ca) and B sites (i.e., replacing Ti or Zr) in the BCTZ lattice and highlighted that the Er-doping-induced vacancy concentration decreases for both the oxygen vacancies (V o) and cation vacancies (V c). Experimentally, the enhanced PL performance and the dielectric, ferroelectric, and piezoelectric properties of the Er-doped BCTZ ceramics have been observed. Finally, the physical origin of Er-induced property enhancement in BCTZ has been elaborated according to the charge density and chemical bonding analysis. These results open up a path to investigate the effects of site substitution and vacancies on optoelectronic properties of multifunctional rare-earth-doped ferroelectrics.

| S-EPMC6648785 | biostudies-literature

Impact of interfacial coupling of oxygen octahedra on ferromagnetic order in La0.7Sr0.3MnO3/SrTiO3 heterostructures.

Project description:La0.7Sr0.3MnO3, a half-metallic ferromagnet with full spin polarization, is generally used as a standard spin injector in heterostructures. However, the magnetism of La0.7Sr0.3MnO3 is strongly modified near interfaces, which was addressed as "dead-layer" phenomenon whose origin is still controversial. Here, both magnetic and structural properties of La0.7Sr0.3MnO3/SrTiO3 heterostructures were investigated, with emphasis on the quantitative analysis of oxygen octahedral rotation (OOR) across interfaces using annular-bright-field imaging. OOR was found to be significantly altered near interface for both La0.7Sr0.3MnO3 and SrTiO3, as linked to the magnetism deterioration. Especially in La0.7Sr0.3MnO3/SrTiO3 superlattices, the almost complete suppression of OOR in 4 unit-cell-thick La0.7Sr0.3MnO3 results in a canted ferromagnetism. Detailed comparisons between strain and OOR relaxation and especially the observation of an unexpected La0.7Sr0.3MnO3 lattice c expansion near interfaces, prove the relevance of OOR for the magnetic properties. These results indicate the capability of tuning the magnetism by engineering OOR at the atomic scale.

| S-EPMC5225431 | biostudies-literature

Amplitude mode in the planar triangular antiferromagnet Na0.9MnO2.

Project description:Amplitude modes arising from symmetry breaking in materials are of broad interest in condensed matter physics. These modes reflect an oscillation in the amplitude of a complex order parameter, yet are typically unstable and decay into oscillations of the order parameter's phase. This renders stable amplitude modes rare, and exotic effects in quantum antiferromagnets have historically provided a realm for their detection. Here we report an alternate route to realizing amplitude modes in magnetic materials by demonstrating that an antiferromagnet on a two-dimensional anisotropic triangular lattice (α-Na0.9MnO2) exhibits a long-lived, coherent oscillation of its staggered magnetization field. Our results show that geometric frustration of Heisenberg spins with uniaxial single-ion anisotropy can renormalize the interactions of a dense two-dimensional network of moments into largely decoupled, one-dimensional chains that manifest a longitudinally polarized-bound state. This bound state is driven by the Ising-like anisotropy inherent to the Mn3+ ions of this compound.

| S-EPMC5988795 | biostudies-literature