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Images of Ga+ -implanted amorphous silicon layers in a 110 n-type silicon substrate have been collected by a range of detectors in a scanning electron microscope and a helium ion microscope. The effects of the implantation dose and imaging parameters (beam energy, dwell time, etc.) on the image contrast were investigated. We demonstrate a similar relationship for both the helium ion microscope Everhart-Thornley and scanning electron microscope Inlens detectors between the contrast of the images and the Ga+ density and imaging parameters. These results also show that dynamic charging effects have a significant impact on the quantification of the helium ion microscope and scanning electron microscope contrast.

Precise and scalable defect engineering of two-dimensional (2D) nanomaterials is acutely sought after in contemporary materials science. Here, we present defect engineering in monolayer graphene and molybdenum disulfide (${\mathrm{MoS}}_{2}$) by irradiation with noble gas ions at 30 keV. Two ion species of different masses were used in a gas field ion source microscope: helium (${\mathrm{He}}^{+}$) and neon (${\mathrm{Ne}}^{+}$). A detailed Raman spectroscopy study was performed and a defect activation model applied with marked differences between the ion systems at a given dose. We propose that disparities between the ion systems are explained by different defect yields and defect sizes. Expanding on existing models, we suggest that the average defect size is smaller for supported than freestanding graphene and that the rate of defect production is larger. We infer that low-energy secondary atoms from the substrate play a significant role in defect production, creating smaller defects relative to those created by the primary ion beam. Furthermore, a similar model was also applied to supported ${\mathrm{MoS}}_{2}$, another promising member of the 2D material family. Defect yields for both ions were obtained for ${\mathrm{MoS}}_{2}$, demonstrating their different interaction with the material and facilitating comparison with other irradiation conditions in the literature.

We report subnanometer modification enabled by an ultrafine helium ion beam. By adjusting ion dose and the beam profile, structural defects were controllably introduced in a few-layer molybdenum disulfide (MoS2) sample and its stoichiometry was modified by preferential sputtering of sulfur at a few-nanometer scale. Localized tuning of the resistivity of MoS2 was demonstrated and semiconducting, metallic-like, or insulating material was obtained by irradiation with different doses of He(+). Amorphous MoSx with metallic behavior has been demonstrated for the first time. Fabrication of MoS2 nanostructures with 7 nm dimensions and pristine crystal structure was also achieved. The damage at the edges of these nanostructures was typically confined to within 1 nm. Nanoribbons with widths as small as 1 nm were reproducibly fabricated. This nanoscale modification technique is a generalized approach that can be applied to various two-dimensional (2D) materials to produce a new range of 2D metamaterials.

Graphene is a promising candidate to succeed silicon based devices and doping holds the key to graphene electronics. Conventional doping methods through surface functionalization or lattice modification are effective in tuning carrier densities. These processes, however, lead to degradation of device performance because of structural defect creation. A challenge remains to controllably dope graphene while preserving its superlative properties. Here we show a novel method for tunable and erasable doping of on-chip graphene, realized by using a focused electron beam. Our results demonstrate site-specific control of carrier type and concentration achievable by modulating the charge distribution in the dielectric substrate. Thereby, the structural integrity and electrical performance of graphene are preserved, and the doping states are rewritable. Different logic operations were thus implemented in a single graphene sheet. By extending this method to other two-dimensional materials, this work lays out a blueprint for powerful yet simple means of incorporating two-dimensional materials into prospective electronic technologies., 19 pages, 5 figures

Graphene coatings have been shown to protect the underlying material from oxidation when exposed to different media. However, the passivating properties of graphene in air at room temperature, which corresponds to the operating conditions of many electronic devices, still remain unclear. In this work, we analyze the oxidation kinetics of graphene/Cu samples in air at room temperature for long periods of time (from 1 day to 113 days) using scanning electron microscopy, conductive atomic force microscopy and Auger electron microscopy, and we compare the results with those obtained for similar samples treated in H2O2. We observe that unlike the graphene sheets exposed to H2O2, in which the accumulation of oxygen at the graphene domain boundaries evolves in a very controlled and progressive way, the local oxidation of graphene in air happens in a disordered manner. In both cases the oxide hillocks formed at the graphene domain boundaries can propagate to the domains until reaching a limiting width and height. Our results demonstrate that the local oxidation of the underlying material along the domain boundaries can dramatically decrease the roughness, conductivity, mechanical resistance and frictional characteristics of the graphene sheet, which reduces the performance of the whole device.

The mechanical properties of ultrathin membranes have attracted considerable attention recently. Nanoindentation based on atomic force microscopy is commonly employed to study mechanical properties. We find that the data processing procedures in previous studies are nice approximations, but it is difficult for them to illustrate the mechanical properties precisely. Accordingly, we develop a revised numerical method to describe the force curve properly, by which the intrinsic mechanical properties of these membranes can be acquired. Combining the nanoindentation measurements with the revised numerical method, we demonstrate that loading-unloading cycles under large load can lead to a pronounced improvement in stiffness of graphene grown by chemical vapor deposition (CVD). The Young's moduli of the stretched CVD graphene membranes can be improved to ∼1 TPa, closing to the value of the pristine graphene. Our findings demonstrate a possible way to recover the exceptional elastic properties of CVD graphene from the softened stiffness caused by wrinkles.

A flexible and efficient method to fabricate nanopores in graphene has been developed. A focused, low-energy (5 keV) electron beam was used to locally activate etching of a graphene surface in a low pressure (0.3 Pa) N2 environment. Nanopores with sub-5 nm diameters were fabricated. The lattice structure of the graphene was observed to recover within 20 nm of the nanopore edge. Nanopore growth rates were investigated systematically. The effects of nitrogen pressure, electron beam dwell time and beam current were characterised in order to understand the etching mechanism and enable optimisation of the etching parameters. A model was developed which describes how the diffusion of ionised nitrogen affects the nanopore growth rate. Etching of other two-dimensional materials was attempted as demonstrated with MoS2. The lack of etching observed supports our model of a chemical reaction-based mechanism. The understanding of the etching mechanism will allow more materials to be etched by selection of an appropriate ion species.

Two-dimensional (2D) materials usually have a layer-dependent work function, which require fast and accurate detection for the evaluation of their device performance. A detection technique with high throughput and high spatial resolution has not yet been explored. Using a scanning electron microscope, we have developed and implemented a quantitative analytical technique which allows effective extraction of the work function of graphene. This technique uses the secondary electron contrast and has nanometre-resolved layer information. The measurement of few-layer graphene flakes shows the variation of work function between graphene layers with a precision of less than 10 meV. It is expected that this technique will prove extremely useful for researchers in a broad range of fields due to its revolutionary throughput and accuracy.

The ability to modify materials at the atomic scale is crucial for the fabrication of functional nanoscale building blocks for novel nanodevices. Consistency and reproducibility of modifications represent the greatest technical challenges, which demand finer structuring capability than the currently available methods. In this chapter, we will present our recent results of sub-nanometer characterization and modification of two-dimensional (2D) materials enabled by an ultrafine helium ion beam. Characterization will be presented not only in terms of lateral dimension measurement, but also with quantitative thickness and work function extraction. This information is obtained from secondary electron imaging. The effect of contamination and charging on our ability to extract such quantitative information will also be assessed. We will demonstrate that structural defects and stoichiometry modification can be controllably introduced in a few-layer molybdenum disulfide (MoS2) sample at a few-nanometer scale. Consequently, localized tuning of the physical properties of MoS2 can be realized. Fabrication of MoS2 nanostructures with 7-nm dimensions and pristine crystal structure has also been achieved, and the effects of beam dose and profile on the modification will be clarified. This nanoscale modification technique is a generalized approach which can be applied to various 2D materials to produce a new range of 2D metamaterials.

Ultrafast-response (20 μs) UV detectors, which are visible-blind and self-powered, in devices where an n-type ZnO nanowire partially lies on a p-type GaN film, are demonstrated. Moreover, a CdSe-nanowire red-light detector powered by a nanoscale ZnO/GaN photovoltaic cell is also demonstrated, which extends the device function to a selective multiwavelength photodetector and shows the function of an optical logical AND gate.

The influence of surface effects on the temperature dependent photoluminescence (PL) spectra from individual ZnO nanowires has been studied. It is found that the surface effects of the nanowire are very important in both ultraviolet (UV) and visible emission. We propose a new luminescence mechanism based on the recombination related to oxygen vacancies to explain the temperature dependent visible emission, which is significantly influenced by the carrier depletion and band bending caused by surface effects. In addition, the observed attenuation of UV emission with increasing temperature is ascribed to the decreasing depletion region and the increasing surface states related nonradiative recombination.

With organic photovoltaic (OPV) technology moving towards commercialisation, high-throughput analytical techniques are required to study the nanoscale morphology of OPV blends. We demonstrate a low-voltage backscattered electron imaging technique in the SEM that combines a solid-state backscattered electron detector with stage biasing to produce a rapid overview of the phase-separated surface morphology of an organic photovoltaic (P3HT:PCBM) blend. Aspects of obtaining the best possible results from the technique are discussed along with the possibility of probing the sub-surface morphology by altering the primary electron beam landing energy.

The graphene-metal contact is very important for optimizing the performance of graphene based electronic devices. However, it is difficult to probe the properties of the graphene/metal interface directly via transport measurements in traditional graphene lateral devices, because the dominated transport channel is graphene, not the interface. Here, we employ the Au/graphene/Au vertical and lateral hybrid structure to unveil the metal-graphene interface properties, where the transport is dominated by the charge carriers across the interface. The magnetoresistance (MR) of Au/monolayer graphene/Au and Au/stacked two-layered graphene/Au devices is measured and modulated by gate voltage, demonstrating that the interface is a device. The gate-tunable MR is identified from the graphene lying on the SiO2 substrate and underneath the top metal electrode. Our unique structures couple the in-plane and out-of-plane transport and display linear MR with small amplitude oscillations at low temperatures. Under a magnetic field, the electronic coupling between the graphene edge states and the electrode leads to the appearance of quantum oscillations. Our results not only provide a new pathway to explore the intrinsic transport mechanism at the graphene/metal interface but also open up new vistas of magnetoelectronics.

Surface organic residues inhibit the extraordinary electronic properties of graphene, hindering the development of graphene electronics. However, fundamental understanding of the residue morphology is still absent due to a lack of high-throughput and high-resolution surface characterization methods. Here, we demonstrate that secondary electron (SE) imaging in the scanning electron microscope (SEM) and helium ion microscope (HIM) can provide sub-nanometer information of a graphene surface and reveal the morphology of surface contaminants. Nanoscale polymethyl methacrylate (PMMA) residues are visible in the SE imaging, but their contrast, i.e. the apparent lateral dimension, varies with the imaging conditions. We have demonstrated a quantitative approach to readily obtain the physical size of the surface features regardless of the contrast variation. The fidelity of SE imaging is ultimately determined by the probe size of the primary beam. HIM is thus evaluated to be a superior SE imaging technique in terms of surface sensitivity and image fidelity. A highly efficient method to reveal the residues on a graphene surface has therefore been established.

Quantized two-terminal conductance plateaus in graphene were observed and were explained through the mechanism of different Landau level filling factors in inhomogeneous sample. Furthermore, the quantized conductance plateaus are different due to the difference of the carrier exchange through the graphene–substrate interface during the increasing and decreasing gate voltage-sweeps.

Electron backscatter diffraction (EBSD) analysis is applied to [0 0 1] oriented magnetite thin films grown on MgO substrates. A high image quality of the Kikuchi patterns was achieved enabling multi-phase scans. Several types of magnetite thin films were analyzed; one as-grown and the others after different annealing steps in oxygen atmosphere. From the EBSD mappings, we learn that the optimum orientation in [0 0 1]-direction is not yet achieved for the as-grown sample, but develops upon oxygen treatment. Furthermore, the distribution of misorientation angles within the investigated area (=1 grain) is found to change during the annealing steps. After 3 min of annealing, most of the misorientations around 30°–40° have vanished, and some islands with high misorientation angles remain, which may play a role as antiferromagnetic pinning centers.

A study to analyse beam damage, image quality and edge contrast in the helium ion microscope (HIM) has been undertaken. The sample investigated was graphene. Raman spectroscopy was used to quantify the disorder that can be introduced into the graphene as a function of helium ion dose. The effects of the dose on both freestanding and supported graphene were compared. These doses were then correlated directly to image quality by imaging graphene flakes at high magnification. It was found that a high magnification image with a good signal to noise ratio will introduce very significant sample damage. A safe imaging dose of the order of 10(13) He(+) cm(-2) was established, with both graphene samples becoming highly defective at doses over 5 × 10(14) He(+) cm(-2).The edge contrast of a freestanding graphene flake imaged in the HIM was then compared with the contrast of the same flake observed in a scanning electron microscope and a transmission electron microscope. Very strong edge sensitivity was observed in the HIM. This enhanced edge sensitivity over the other techniques investigated makes the HIM a powerful nanoscale dimensional metrology tool, with the capability of both fabricating and imaging features with sub-nanometre resolution.

Bi₂Se₃ nanocrystals with various morphologies, including nanotower, nanoplate, nanoflake, nanobeam and nanowire, have been synthesized. Well-distinguished Shubnikov-de Haas (SdH) oscillations were observed in Bi₂Se₃ nanoplates and nanobeams. Careful analysis of the SdH oscillations suggests the existence of Berry's phase π, which confirms the quantum transport of the surface Dirac fermions in both Bi₂Se₃ nanoplates and nanobeams without intended doping. The observation of the singular quantum transport of the topological surface states implies that the high-quality Bi₂Se₃ nanostructures have superiorities for investigating the novel physical properties and developing the potential applications.

Graphene has various potential applications owing to its unique electronic, optical, mechanical and chemical properties, which are primarily based on its two-dimensional nature. Graphene-based vertical devices can extend the investigations and potential applications range to three dimensions, while interfacial properties are crucial for the function and performance of such graphene vertical devices. Here we report a general method to construct graphene vertical devices with controllable functions via choosing different interfaces between graphene and other materials. Two types of vertically conducting devices are demonstrated: graphene stacks sandwiched between two Au micro-strips, and between two Co layers. The Au|graphene|Au junctions exhibit large magnetoresistance with ratios up to 400% at room temperature, which have potential applications in magnetic field sensors. The Co|graphene|Co junctions display a robust spin valve effect at room temperature. The layer-by-layer assembly of graphene offers a new route for graphene vertical structures.

A focused helium ion beam was used to introduce nano-sized gap chains in graphene. The effect of beam scanning strategies in the fabrication of the nano-gap chains was investigated. The tuning of graphene conductivity has been achieved by modulating the magnitude and uniformity of the ion dose and hence the morphology of the nano-gap chains. A model based on the site-specific and dose-dependent conductivity was built to understand the tuning of the conductivity, taking into account the nanoscale non-uniformity of irradiation.

A large magnetoresistance (MR) effect of few-layers graphene between two non-magnetic metal electrodes with current perpendicular to graphene plane is studied. A non-saturation and anisotropic MR with the value over 60% at 14 T is observed in a two-layer graphene stack at room temperature. The resistance of the device is only tens of ohms, having the advantage of low power consumption for magnetic device applications.

A seven orders of magnitude increase in the current on/off ratio of ZnO nanowire field-effect transistors (FETs) after Ga( + ) irradiation was observed. Transmission electron microscopy characterization revealed that the surface crystal quality of the ZnO nanowire was improved via the Ga( + ) treatment. The Ga( + ) irradiation efficiently reduces chemisorption effects and decreases oxygen vacancies in the surface layer. The enhanced performance of the nanowire FET was attributed to the decrease of surface trapped electrons and the decrease in carrier concentration.

The current-voltage (I-V) characteristics of single ZnO nanowires were measured varying with temperature and illumination. A model of the ZnO nanowire sandwiched by back-to-back diodes was utilized to explain the experimental data. Simulations of the I-V curves exhibited that the surface barrier height was independent of temperature from 180 to 290 K. This work also shows that the larger the incident laser power is, the smaller the contact surface barrier height will be. The photon induced reduction in the surface barrier height is attributed to the photogenerated holes, which result in a shielding effect on the surface trapped electrons.

Defects in ferrite can change the local magnetic coupling from ferromagnetic to strongly antiferromagnetic. In eptiaxial magnetite (Fe3O4) films, defects locally altering exchange interaction, i.e., "antiphase boundaries" (APB), essentially determine magnetic and magnetotransport properties. We locally observed specific magnetization reversal events in epitaxial magnetite Fe3-delta O4/MgO films (delta approximate to 0.03) by magnetic force microscopy in external magnetic fields. A dominating phenomenon is pinning of bubble domains at single APB. Pinning is a particular consequence of antiferromagnetic coupling across APB. Antiferromagnetic coupling across APB could be directly verified for a sample with an APB domain size above the resolution limit of magnetic force microscopy.

Fe3O4[001] thin films is grown on MgO[001] substrates using oxygen-plasma-assisted molecular beam epitaxy and annealed in air at 250 degC. Automated EBSD scans is performed twice to study the crystallographic orientation by means of recording of Kikuchi patterns.

We investigate magnetotransport in the vicinity of the charge neutral point (CNP) in bilayer graphene at low temperatures. The CNP is found to vary with applied magnetic fields. Through measuring the transfer curves under different magnetic fields and at different temperatures, the temperature dependence of the peak resistivity at the CNP and under a fixed magnetic field is extracted. At low temperatures, it is found that the peak resistivity at the CNP increases exponentially with decreasing temperature under 14 T, which indicates the gap opening in zero-energy Landau level. The origins of such magnetic field induced insulating behavior are discussed.

We report the magnetoresistance (MR) in single-layer graphene field-effect transistors at different gate voltages. At low temperatures, the MR exhibits fluctuations at Dirac point, which is attributed to quantum interference effect. Apart from the Dirac point, the MR shows a linear behavior under the extreme quantum limit that is identified by Shubnikov-de Haas oscillations and quantum Hall effect. Our experimental results give a clear manifestation of the quantum linear MR.

It has recently been predicted that the surface plasmons are allowed to exist on the interface between a topological insulator and vacuum. Surface plasmons can be employed to enhance the optical emission from various illuminants. Here, we study the photoluminescence properties of the ZnO/Bi2Te3 hybrid structures. Thin flakes of Bi2Te3, a typical three-dimensional topological insulator, were prepared on ZnO crystal surface by mechanical exfoliation method. The ultraviolet emission from ZnO was found to be enhanced by the Bi2Te3 thin flakes, which was attributed to the surface plasmon – photon coupling at the Bi2Te3/ZnO interface.

time, and recovery speed of our UV detectors are 8 � 10 2 , 0.7s, and 0.5s, respectively, which are significantly improved compared to the conventional ZnO NWs photodetectors. The improved performance is attributed to the existence of Schottky barriers between ZnO NW and graphene electrodes. The graphene/ZnO NW/graphene vertical sandwiched structures may be promising candidates for integrated optoelectronic sensor devices. V C 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4724208] ZnO, as a wide direct band gap (3.37eV) compound semiconductor with large exciton binding energy (60meV), has been widely investigated for its potential applications in optoelectronic devices, gas and chemical sensors. 1,2 Due to large surface-to-volume ratio, ZnO nanowires (NWs) exhibit highly susceptible photoelectric properties by means of electron-hole generation or recombination during ultraviolet (UV) illumination. Therefore, ZnO NWs have great potential in high sensitivity and fast-response UV sensors, 3 environmental monitors, and optical communications. 4 Recently, Hu et al. 5 reported ZnO NW based UV sensors using Schottky contact formed between ZnO and Pt electrode and the device performance such as the sensitive and UV response, is much higher than that of the traditional ZnO NW photoconductivity based UV sensors. The UV detectors based on Schottky barriers formed between ZnO NW and other metal electrodes, such as gold electrodes, have also been studied. 6,7 Nevertheless, metal electrodes are poor in transparency and can dramatically influence the absorption efficiency of the UV sensors. Graphene, a monolayer sp 2 carbon atoms with unique physical properties, such as high mobility and conductivity, 8 high optical transparency 9 and mechanical flexibility, 10 etc., has attracted great research interest recently. The high conductive and optical transparent properties make graphene an ideal candidate for the application in transparent electrode. The Schottky barrier is also expected to be existed at the interface between ZnO nanowire and graphene, and it has been utilized for light-emitting diodes 11 and transparent nanogenerators. 12 In this letter, we have fabricated a vertical sandwich structure of graphene/ZnO NW/graphene. We demonstrate the high performance of our ZnO NW based vertical UV photodetector due to the existence of Schottky barriers between graphene electrodes and ZnO NW. The current on-off ratio of the UV detector is up to 8 � 10 2 at a illumination power density of 50lw/lm 2 , the photocurrent

The strain dependence of conductance of monolayer graphene has been studied experimentally here. The results illustrate the notable transitions: the slight increase, the dramatic decrease, and the sudden dropping of the conductance by gradually increasing the uniaxial strain. The graphene conductance behaves reversibly by tuning of the elastic tensile strain up to 4.5%, while it fails to recover after the plastic deformation at 5%. The change in conductance due to strain is surprisingly high, which indicates the potential applications in electromechanical devices.

Photoluminescence (PL) properties of individual CdSe nanowires with diameters beyond the quantum confinement regime have been studied. A blue-shift in the PL spectra was observed with decreasing nanowire diameter. We attribute the blue-shift to band-filling effect. Carrier density induced by surface vacancy doping and laser excitation is found to be high enough to meet the criterion of the band-filling effect and increases with decreasing nanowire diameter. Temperature dependent PL analysis and characterizations of a single CdSe nanowire based field-effect transistor were also performed.

Artificial disorder was introduced gradually into monolayer graphene by controlling Ga+ ion irradiation and the corresponding electronic transport properties regulated by gate voltage, source-drain voltage, temperature, and magnetic field were studied experimentally. An unsaturated positive magnetoresistance (MR) up to 100% at ∼5 T was observed in as-fabricated graphene, while there is significant negative MR in disordered graphene. This phenomenon was attributed to the monocrystalline breaking and crystallite-boundary scattering in disordered graphene.

Magnetoresistance (MR) in bilayer graphene was experimentally investigated by varying magnetic-field strength. A transition from classical MR (superlinear dependence (B 4/3 )) to quantum MR (Shubnikov-de Haas oscillations) was observed at a magnetic field of about 10T. The superlinear MR dependence is described using a classical route by considering the large inhomogenous mobility spatial distribution of charge carriers. Our experimental results may help to provide a clear physical picture of the magneto-transport properties of inhomogenous graphene. Copyright c EPLA, 2011

The relationship between the electrical properties and structure evolution of single layer graphene was studied by gradually introducing the gallium ion irradiation. Raman spectrums show a structural transition from nano-crystalline graphene to amorphous carbon as escalating the degree of disorder of the graphene sample, which is in correspondence with the electrical transition from a Boltzmann diffusion transport to a carrier hopping transport. The results show a controllable method to tune the properties of graphene.

We report experimental results on the universal conductance fluctuations (UCFs) in the bilayer graphene system. The UCF properties under different temperatures, magnetic fields and current bias were investigated. An anomalous current-dependent UCF was observed: the rms amplitude of the conductance fluctuations is inversely proportional to the current bias. The detailed physical mechanisms were discussed by involving the confined scattering of chiral fermions in graphene.

To enhance performances of graphene/SiO(2) based field-effect transistors (FETs), understanding of the transfer of carriers through the graphene/SiO(2) interface is crucial. In this paper, we have studied the temperature dependent transfer characters of graphene FETs. Hysteresis loop is shown to be dominated by trapping/detrapping carriers through the graphene/SiO(2) interface.

The influence of the barrier between metal electrodes and graphene on the electrical properties was studied on a two-electrode device. A classical barrier model was used to analyze the current-voltage characteristics. Primary parameters including barrier height and effective resistance were achieved. The electron transport properties under magnetic field were further investigated. An abnormal peak-valley-peak shape of voltage-magnetoresistance curve was observed. The underlying mechanisms were discussed under the consideration of the important influence of the contact barrier. Our results indicate electrical properties of graphene based devices are sensitive to the contact interface.

We studied the influence of adsorbates on the space-charge-limited current (SCLC) in individual ZnO nanowires through varying the bias voltage, laser illumination, and ambient pressure. In dark and air conditions, the free carriers were depleted by the surface adsorbates, and electrons injected from the electrode to the nanowire dominated the electron transport properties. Under laser illumination, the current-voltage characteristic was linear at low voltage and superlinear at high voltage, and the SCLC regime occurred at high voltages due to the surface desorption. The time response of photoconductivity further revealed the dynamic process of elimination of SCLC by desorption of oxygen molecules at the ZnO nanowire surface.

Magnetite thin films grown on [001] oriented MgO substrates are analyzed by means of electron backscatter diffraction (EBSD) analysis and magnetic force microscopy in applied fields. The EBSD technique enables the crystallographic orientation of individual grains to be determined with a high spatial resolution up to 20nm on such ceramic samples. A high image quality of the recorded Kikuchi patterns was achieved enabling multiphase scans and high spatial resolution measurements. Upon annealing in air, the magnetic properties of the magnetite thin films were found to change considerably. Using the EBSD analysis, we find that misoriented grains remaining after the annealing step form small islands with a size of about 100nm. The size and distribution of these islands correspond well to the observations of antiferromagnetic pinning centers within the magnetic domain structures carried out by magnetic force microscopy on the same samples.

A long-range ordered magnetic domain structure was found in magnetitelike (Fe3−δO4, δ≈0.03) thin films prepared by molecular beam epitaxy on MgO (100) substrates. The stripelike magnetic domain structure arising after suitable postprocessing differs significantly from earlier observations. The field-dependent domain structure was investigated by magnetic force microscopy in external magnetic fields. The magnetic domain structure results from a moderate perpendicular anisotropy. The domain structure is pinned, and the pinning centers arise from the magnetite antiphase domain structure.