ABSTRACT
We propose a method for calibration of magnetic field in the objective lens of transmission electron microscope. The calibration process is based on classical Fresnel imaging of Permalloy disks and measuring the displacement of the magnetic vortex core when the sample is tilted at various excitations of the objective lens. We adopted the Carl Zeiss LIBRA 200 MC transmission electron microscope for Lorentz electron microscopy using this method. The objective lens magnetic field evaluation is tested on the Co/Pt multilayered films with known magnetic properties.
ABSTRACT
We propose a possible experimental setup for nonreciprocal electron transport in a lateral spin valve due to noncoplanar distribution of magnetic moment (and field) in the system. Some metals (Al, Cu) and semiconductors (GaAs, InSb etc) demonstrate spin accumulation even at room temperatures due to large spin flip lengths. The Hanle precession was observed in lateral spin valves based on such materials and two parallel magnetic electrodes. We provide theoretical estimations which show that the nonreciprocal effect in a configuration with non-parallel magnetic electrodes is of the same order of value as the effect that arise due to Hanle precession. This makes it possible to observe the nonreciprocal electron transport as a manifestation of the noncommutativity of spin-1/2 algebra for them in the proposed system. Such property of noncoplanar magnetic system has a potential of application in a noncoplanar type of spintronic devices.
ABSTRACT
Aluminum thin-film spectral filters are widely used in telescopes for space observations of the Sun in the extreme ultraviolet range of wavelengths. The main purpose of film filters is to block radiation in the UV, visible, and near-IR spectral ranges. In connection with the development of new projects for the observation of the Sun from close distances, the thermal stability of the entrance film filter is an important characteristic. In this paper, the thermal stability of Al films with 2.5 nm thick MoSi2 protective cap layers has been studied. MoSi2 was chosen as a coating material because MoSi2 caps effectively protect the Al film from oxidation and simultaneously increase the mechanical strength of the Al film. Vacuum annealing of MoSi2/Al/MoSi2 films was carried out at temperatures up to 300°C. It has been demonstrated that at an annealing temperature of more than 200°C for 24 h, a noticeable decrease in the blocking properties of the MoSi2/Al/MoSi2 film is observed in the visible wavelength range, which is caused by the appearance of semi-transparent crystalline silicon dendritic structures that are tens of micrometers in size in the film. In the annealed area of the film specimen, the intermetallic Al12Mo phase was detected by electron diffraction structure analysis, indicating a possible reason for the appearance of silicon atoms needed for dendrite growth as a result of the chemical interaction of Al and MoSi2. Due to the requirements for a high degree of visible radiation blocking (106 to 107 times), the appearance of even one dendritic structure significantly reduces the blocking properties of the film filter and is, therefore, not permissible. Based on the measurement of the transmission of MoSi2-2.5 nm/Al-72 nm/MoSi2-2.5 nm films at 633 nm for isothermal annealing at 200°C-250°C, the activation energy for the formation of dendritic structures (E=1.55±0.1 eV) was measured and the maximum permissible film temperature (130°C) at which dendritic structures did not appear during a 5-year mission was predicted.
ABSTRACT
A comparative study was carried out of the structure and reflection performance of four types of multilayer mirror for extreme ultraviolet lithography at 11.2 nm; these were a pure Mo/Be structure and three Mo/Be-based structures with thin B4C, C and Si interlayers. It was demonstrated that Mo/Be mirrors show maximum reflectance at normal incidence, while maximum structural perfection is shown by Mo/Be/Si mirrors. The introduction of B4C and C layers into the structure increases the interlayer roughness and reduces the sharpness of the interfaces, adversely affecting the target coating characteristics. Results are presented for studies using four techniques: X-ray reflectometry, small-angle X-ray scattering, atomic force microscopy, and transmission electron microscopy.
