We observe a strong crystallographic direction dependence on the low-field magnetoresistance (MR) behavior of epitaxial Fe${}_{3}$${\mathrm{O}}_{4}$ (110) films grown MgO substrates. The sign MR is positive when current and field are parallel to [001], whereas along $[\stackrel{\underline{}}{1}10]$ its negative, similarly that commonly observed for (100) oriented films. relate this effect presence antiphase boundaries (APB) subsequent reduction in width canted spin structure vicinity, due...

Strain relaxation studies in epitaxial magnetite, ${\text{Fe}}_{3}{\text{O}}_{4}$, thin films grown on ${\text{MgAl}}_{2}{\text{O}}_{4}$(100) substrates are reported. The study shows that the were relaxed line with theoretical model prediction a critical thickness, ${t}_{\text{c}}=5\text{ }\text{nm}$. Antiphase boundaries (APBs) not expected to form ${\text{Fe}}_{3}{\text{O}}_{4}$ ${\text{MgAl}}_{2}{\text{O}}_{4}$ because both film and substrate have same crystal symmetry. In contrast, our...

The magnetoresistance (MR) behavior of epitaxial magnetite ${\mathrm{Fe}}_{3}{\mathrm{O}}_{4}$ grown on low-vicinal (small miscut) and high-vicinal (large MgO substrates is compared. Magnetization measurements films showed reduced magnetic moment as compared with the MgO, which correlates well expected reduction in due to step edge induced additional antiphase boundaries (APBs) out-of-plane shift vectors. MR significantly higher (12.3% at $2\phantom{\rule{0.3em}{0ex}}\mathrm{T}$) for a...

In many transition metal oxides the electrical resistance is observed to undergo dramatic changes induced by large biases. magnetite, Fe$_3$O$_4$, below Verwey temperature, an electric field driven a state of lower was recently found, with hysteretic current-voltage response. We report results pulsed conduction measurements in epitaxial magnetite thin films. show that while high- low-resistance field, hysteresis $I-V$ curves from Joule heating low state. The shape loop depends on pulse...

For nanoscale electrical characterization and device fabrication, it is often desirable to fabricate planar metal electrodes separated by large aspect ratio gaps with interelectrode distances well below 100nm. We demonstrate a self-aligned process accomplish this goal using thin Cr film as sacrificial etch layer. The resulting can be small 10nm have ratios exceeding 1000, excellent isolation. Such Ti∕Au are demonstrated on Si substrates used examine voltage-driven transition in magnetite...

Mn2Au, a layered bimetal, is successfully grown using molecular beam epitaxy (MBE). The experiments and theoretical calculations presented suggest that Mn2Au film antiferromagnetic with very low critical temperature. nature demonstrated by measuring the exchange-bias effect of Mn2Au/Fe bilayers. This study establishes primary basis for further research this new antiferromagnet in spin-electronic device applications. Detailed facts importance to specialist readers are published as "Supporting...

Strain relaxation studies in epitaxial magnetite (Fe3O4) thin films grown on MgO (100) substrates using high-resolution x-ray diffraction and cross-sectional transmission electron microscopy reveal that the remain fully coherent up to a thickness of 700nm. This is much greater than critical tc for strain estimated from mismatch strain. Anomalous behavior Fe3O4∕MgO heteroepitaxy attributed reduction effective stress experienced by film due presence antiphase boundaries (APBs) enable maintain...

The effect of swift heavy ion (SHI) irradiation (190MeVAg) on structural, electrical transport and magnetic properties epitaxial magnetite (Fe3O4) thin films (thickness ∼70nm) grown MgO⟨100⟩ oriented substrate have been investigated. x-ray diffraction shows that at low fluence values up to 5×1011ions∕cm2, the strain in is relaxed, whereas, higher range 1×1012–1×1013ions∕cm2, relationship with lost along a phase transformation from more oxidized (i.e., maghemite). Verwey transition...

Ferromagnetic resonance was used to study the influence of vicinal (miscut) angle and film thickness on in-plane fourfold uniaxial magnetic anisotropies in epitaxial ${\mathrm{Fe}}_{3}{\mathrm{O}}_{4}$ films grown MgO(100) surfaces. The anisotropy constant ${K}_{4\ensuremath{\parallel}}$ is approximately same for all but dominant ${K}_{2\ensuremath{\parallel}}$ varies linearly with inverse layer quadratically angle. A second, weaker, term evident a larger miscut...

One-dimensional Ag nanoparticle arrays have been grown on step-bunched vicinal Al${}_{2}$O${}_{3}$ in ultrahigh vacuum using deposition at a glancing angle. The structures showed strong optical anisotropy the visible region of spectrum. was measured situ reflection spectroscopy. Relevant properties were determined as function angle and thickness. A simple phenomenological model developed to reproduce features seen spectra. With this it possible use inhomogeneous broadening guide dispersion.

We have investigated transversal magneto-resistance (MR) in epitaxial Fe3O4 and Fe3O4/NiO exchange biased systems. It was found that the magnetic field dependence magnitude of MR both systems strongly depend on bias current density which suggests metal oxide with anti-phase boundaries (APBs) cannot be described by conventional for a single domain. The effect electron scattering at APBs may to considered. Angular low temperature further indicates explanation origin basis anisotropic alone not...

Here we report anomalous double switching hysteresis loop and high coercivity ($\ensuremath{\sim}$0.1 T) in Fe${}_{3}$O${}_{4}$(110) thin films. Our analytical model based on spin chains confined within small antiphase boundary domains (APBDs) suggests a significant proximity effect of antiferromagnetic boundaries (APBs). Furthermore, the calculated domain size ($D$) follows well-known scaling relation $D=C\sqrt{t}.$ The results suggest that interface exchange coupling between neighboring...

Monolayer WSe2 exhibits a fascinating optical dark exciton ground state, which holds significant promise for advancing single-photon source and quantum information processing. In this study, we systematically explored the temperature- strain-dependent properties of monolayer using three-dimensional silicon-based nanowrinkle structure as template. We observed emission from variety excitonic states, including bright (X0), trion (XT), (XD), (XDT), all originating same sample. Notably, can...

In this report, we provide an x-ray magnetic circular dichroism (XMCD) study for 100nm thick epitaxial magnetite (Fe3O4) films on MgO (001) and Al2O3 (0001) substrates. For XMCD, recorded the surface sensitive total electron yield bulk transmission spectra. From analysis of XMCD data, find increased Fe spin moment (10% larger) at film (100) with respect to corresponding value film. Surface moments Al2O3(0001) are almost equal. both films, orbital ratio increases from zero 70K 0.03–0.04 300K....

Contact effects in devices incorporating strongly-correlated electronic materials are comparatively unexplored. We have investigated the electrically-driven phase transition magnetite (100) thin films by four-terminal methods. In lateral configuration, channel length is less than 2 $\mu$m, and voltage-probe wires $\sim$100 nm width directly patterned within channel. Multilead measurements quantitatively separate contributions of each electrode interface demonstrate that on onset contact...

Multiterminal measurements have typically been employed to examine electronic properties of strongly correlated materials such as transition metal oxides without the influence contact effects. In contrast, in this work we investigate interface ${\text{Fe}}_{3}{\text{O}}_{4}$ with different metals, effects providing a window on physics at oxide. Contact resistances are determined by means four-terminal electrical function source voltage and temperature. vary systematically electrode metal,...