Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Magnetic and transport properties of epitaxial thin film MgFe2O4 grown on MgO (100) by molecular beam epitaxy.

ABSTRACT: Magnesium ferrite is a very important magnetic material due to its interesting magnetic and electrical properties and its chemical and thermal stability. Here we report on the magnetic and transport properties of epitaxial MgFe2O4 thin films grown on MgO (001) by molecular beam epitaxy. The structural properties and chemical composition of the MgFe2O4 films were characterized by X-Ray diffraction and X-Ray photoelectron spectroscopy, respectively. The nonsaturation of the magnetization in high magnetic fields observed for M (H) measurements and the linear negative magnetoresistance (MR) curves indicate the presence of anti-phase boundaries (APBs) in MgFe2O4. The presence of APBs was confirmed by transmission electron microscopy. Moreover, post annealing decreases the resistance and enhances the MR of the film, suggesting migration of the APBs. Our results may be valuable for the application of MgFe2O4 in spintronics.

SUBMITTER: Wu HC

PROVIDER: S-EPMC4228329 | biostudies-other | 2014

REPOSITORIES: biostudies-other

ACCESS DATA

Json Xml

Similar Datasets

Structural, Magnetic, and Magneto-Optical Properties of Thin Films of BaM Hexaferrite Grown by Laser Molecular Beam Epitaxy.

Project description:Thin films of BaM hexaferrite (BaFe12O19) were grown on α-Al2O3(0001) substrates by laser molecular beam epitaxy. Structural, magnetic, and magneto-optical properties were studied using medium-energy ion scattering, energy dispersive X-ray spectroscopy, atomic force microscopy, X-ray diffraction, magneto-optical spectroscopy, and magnetometric techniques, and the dynamics of magnetization by ferromagnetic resonance method. It was shown that even a short time annealing drastically changes the structural and magnetic properties of films. Only annealed films demonstrate magnetic hysteresis loops in PMOKE and VSM experiments. The shape of hysteresis loops depends on thickness of films showing practically rectangular loops and high value of remnant magnetization (Mr/Ms~99%) for thin films (50 nm) and much broader and sloped loops in thick (350-500 nm) films. The magnitude of magnetization 4πMs ≈ 4.3 kG in thin films corresponds to that in bulk BaM hexaferrite. Photon energy and sign of bands in magneto-optical spectra of thin films correspond to ones observed earlier in bulk samples and films of BaM hexaferrite. FMR spectra of 50 nm films at 50 GHz consist of a number of narrow lines. The width of main line ΔH~20 Oe is lower than has been reported up to now.

| S-EPMC10302779 | biostudies-literature

Highly Oriented Atomically Thin Ambipolar MoSe2 Grown by Molecular Beam Epitaxy.

Project description:Transition metal dichalcogenides (TMDCs), together with other two-dimensional (2D) materials, have attracted great interest due to the unique optical and electrical properties of atomically thin layers. In order to fulfill their potential, developing large-area growth and understanding the properties of TMDCs have become crucial. Here, we have used molecular beam epitaxy (MBE) to grow atomically thin MoSe2 on GaAs(111)B. No intermediate compounds were detected at the interface of as-grown films. Careful optimization of the growth temperature can result in the growth of highly aligned films with only two possible crystalline orientations due to broken inversion symmetry. As-grown films can be transferred onto insulating substrates, allowing their optical and electrical properties to be probed. By using polymer electrolyte gating, we have achieved ambipolar transport in MBE-grown MoSe2. The temperature-dependent transport characteristics can be explained by the 2D variable-range hopping (2D-VRH) model, indicating that the transport is strongly limited by the disorder in the film.

| S-EPMC5492213 | biostudies-literature

Magnetic Field Enhanced Superconductivity in Epitaxial Thin Film WTe2.

Project description:In conventional superconductors an external magnetic field generally suppresses superconductivity. This results from a simple thermodynamic competition of the superconducting and magnetic free energies. In this study, we report the unconventional features in the superconducting epitaxial thin film tungsten telluride (WTe2). Measuring the electrical transport properties of Molecular Beam Epitaxy (MBE) grown WTe2 thin films with a high precision rotation stage, we map the upper critical field Hc2 at different temperatures T. We observe the superconducting transition temperature T c is enhanced by in-plane magnetic fields. The upper critical field Hc2 is observed to establish an unconventional non-monotonic dependence on temperature. We suggest that this unconventional feature is due to the lifting of inversion symmetry, which leads to the enhancement of Hc2 in Ising superconductors.

| S-EPMC5917024 | biostudies-literature

Structural properties of Bi thin film grown on Si (111) by quasi-van der Waals epitaxy.

Project description:Crystallinity of an 80-nm-thick bismuth thin film grown on Si (111) substrate by MBE was investigated. The highly (0003) textured Bi film contains two twinning domains with different bilayer stacking sequences. The basic lattice parameters c and a as well as b, the bilayer thickness, of the two domains were determined from a series of X-ray diffraction (XRD) measurements, and found that the differences are within 0.1% as compared with those of bulk Bi reported in literature, suggesting that the Bi film has been nearly fully relaxed. From the XRD φ-scans of asymmetric Bi (01-14), (10-15), (11-26) planes and Si (220) plane as well as selected area electron diffraction patterns and electron back scatter diffraction pole figures, we confirmed the well registration between the lattices of Si and Bi lattice, i.e. the ω angle difference between Bi[0003] and Si[111] and the φ angle difference between Bi[01-14] and Si[220] are 0.056° and 0.25°, respectively, and thus concluded that the growth is a quasi-van der Waals epitaxy.

| S-EPMC8854617 | biostudies-literature

Freestanding epitaxial SrTiO3 nanomembranes via remote epitaxy using hybrid molecular beam epitaxy.

Project description:The epitaxial growth of functional oxides using a substrate with a graphene layer is a highly desirable method for improving structural quality and obtaining freestanding epitaxial nanomembranes for scientific study, applications, and economical reuse of substrates. However, the aggressive oxidizing conditions typically used in growing epitaxial oxides can damage graphene. Here, we demonstrate the successful use of hybrid molecular beam epitaxy for SrTiO3 growth that does not require an independent oxygen source, thus avoiding graphene damage. This approach produces epitaxial films with self-regulating cation stoichiometry. Furthermore, the film (46-nm-thick SrTiO3) can be exfoliated and transferred to foreign substrates. These results open the door to future studies of previously unattainable freestanding oxide nanomembranes grown in an adsorption-controlled manner by hybrid molecular beam epitaxy. This approach has potentially important implications for the commercial application of perovskite oxides in flexible electronics and as a dielectric in van der Waals thin-film electronics.

| S-EPMC9788776 | biostudies-literature

Electronic correlations in epitaxial CrN thin film.

Project description:Chromium nitride (CrN) spurred enormous interest due to its coupled magnetostructural and unique metal-insulator transition. The underneath electronic structure of CrN remains elusive. Herein, the electronic structure of epitaxial CrN thin film has been explored by employing resonant photoemission spectroscopy (RPES) and X-ray absorption near edge spectroscopy study in combination with the first-principles calculations. The RPES study indicates the presence of a charge-transfer screened 3[Formula: see text] ([Formula: see text]: hole in the N-2[Formula: see text]) and 3[Formula: see text] final-states in the valence band regime. The combined experimental electronic structure along with the orbital resolved electronic density of states from the first-principles calculations reveals the presence of Cr(3[Formula: see text])-N(2[Formula: see text]) hybridized (3[Formula: see text]) states between lower Hubbard (3[Formula: see text]) and upper Hubbard (3[Formula: see text]) bands with onsite Coulomb repulsion energy (U) and charge-transfer energy ([Formula: see text]) estimated as [Formula: see text] 4.5 and 3.6 eV, respectively. It verifies the participation of ligand (N-2[Formula: see text]) states in low energy charge fluctuations and provides concrete evidence for the charge-transfer ([Formula: see text]U) insulating nature of CrN thin film.

| S-EPMC10519984 | biostudies-literature

Quantized anomalous Hall resistivity achieved in molecular beam epitaxy-grown MnBi2Te4 thin films.

Project description:The intrinsic magnetic topological insulator MnBi2Te4 provides a feasible pathway to the high-temperature quantum anomalous Hall (QAH) effect as well as various novel topological quantum phases. Although quantized transport properties have been observed in exfoliated MnBi2Te4 thin flakes, it remains a big challenge to achieve molecular beam epitaxy (MBE)-grown MnBi2Te4 thin films even close to the quantized regime. In this work, we report the realization of quantized anomalous Hall resistivity in MBE-grown MnBi2Te4 thin films with the chemical potential tuned by both controlled in situ oxygen exposure and top gating. We find that elongated post-annealing obviously elevates the temperature to achieve quantization of the Hall resistivity, but also increases the residual longitudinal resistivity, indicating a picture of high-quality QAH puddles weakly coupled by tunnel barriers. These results help to clarify the puzzles in previous experimental studies on MnBi2Te4 and to find a way out of the big difficulty in obtaining MnBi2Te4 samples showing quantized transport properties.

| S-EPMC10776363 | biostudies-literature

InPBi single crystals grown by molecular beam epitaxy.

Project description:InPBi was predicted to be the most robust infrared optoelectronic material but also the most difficult to synthesize within In-VBi (V = P, As and Sb) 25 years ago. We report the first successful growth of InPBi single crystals with Bi concentration far beyond the doping level by gas source molecular beam epitaxy. The InPBi thin films reveal excellent surface, structural and optical qualities making it a promising new III-V compound family member for heterostructures. The Bi concentration is found to be 2.4 ± 0.4% with 94 ± 5% Bi atoms at substitutional sites. Optical absorption indicates a band gap of 1.23 eV at room temperature while photoluminescence shows unexpectedly strong and broad light emission at 1.4-2.7 μm which can't be explained by the existing theory.

| S-EPMC4071318 | biostudies-other

Investigation of Localized States in GaAsSb Epilayers Grown by Molecular Beam Epitaxy.

Project description:We report the carrier dynamics in GaAsSb ternary alloy grown by molecular beam epitaxy through comprehensive spectroscopic characterization over a wide temperature range. A detailed analysis of the experimental data reveals a complex carrier relaxation process involving both localized and delocalized states. At low temperature, the localized degree shows linear relationship with the increase of Sb component. The existence of localized states is also confirmed by the temperature dependence of peak position and band width of the emission. At temperature higher than 60 K, emissions related to localized states are quenched while the band to band transition dominates the whole spectrum. This study indicates that the localized states are related to the Sb component in the GaAsSb alloy, while it leads to the poor crystal quality of the material, and the application of GaAsSb alloy would be limited by this deterioration.

| S-EPMC4933967 | biostudies-literature

Strain-Engineered Graphene Grown on Hexagonal Boron Nitride by Molecular Beam Epitaxy.

Project description:Graphene grown by high temperature molecular beam epitaxy on hexagonal boron nitride (hBN) forms continuous domains with dimensions of order 20 μm, and exhibits moiré patterns with large periodicities, up to ~30 nm, indicating that the layers are highly strained. Topological defects in the moiré patterns are observed and attributed to the relaxation of graphene islands which nucleate at different sites and subsequently coalesce. In addition, cracks are formed leading to strain relaxation, highly anisotropic strain fields, and abrupt boundaries between regions with different moiré periods. These cracks can also be formed by modification of the layers with a local probe resulting in the contraction and physical displacement of graphene layers. The Raman spectra of regions with a large moiré period reveal split and shifted G and 2D peaks confirming the presence of strain. Our work demonstrates a new approach to the growth of epitaxial graphene and a means of generating and modifying strain in graphene.

| S-EPMC4772548 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data