Search results for "Electron diffraction"

High quality epitaxial Mn 2 Au (001) thin films grown by molecular beam epitaxy

2020

The recently discovered phenomenon of Neel spin–orbit torque in antiferromagnetic Mn2Au [Bodnar et al., Nat. Commun. 9, 348 (2018); Meinert et al., Phys. Rev. Appl. 9, 064040 (2018); Bodnar et al., Phys. Rev. B 99, 140409(R) (2019)] has generated huge interest in this material for spintronics applications. In this paper, we report the preparation and characterization of high quality Mn2Au thin films by molecular beam epitaxy and compare them with magnetron sputtered samples. The films were characterized for their structural and morphological properties using reflective high-energy electron diffraction, x-ray diffraction, x-ray reflectometry, atomic force microscopy, and temperature dependen…

Low energy nano diffraction (LEND) – A versatile diffraction technique in SEM

2019

Abstract Electron diffraction is a powerful characterization method that is used across different fields and in different instruments. In particular, the power of transmission electron microscopy (TEM) largely relies on the capability to switch between imaging and diffraction mode enabling identification of crystalline phases and in-depth studies of crystal defects, to name only examples. In contrast, while diffraction techniques have found their way into the realm of scanning electron microscopy (SEM) in the form of electron backscatter diffraction and related techniques, on-axis transmission diffraction is still in its infancy. Here we present a simple but versatile setup that enables a ‘…

Fast-ADT: A fast and automated electron diffraction tomography setup for structure determination and refinement.

2020

Abstract Electron crystallography has focused in the last few years on the analyses of microcrystals, mainly organic compounds, triggered by recent publications on acquisition methods based on direct detection cameras and continuous stage tilting. However, the main capability of a transmission electron microscope is the access to features at the nanometre scale. In this context, a new acquisition method, called fast and automated diffraction tomography (Fast-ADT), has been developed in form of a general application in order to get the most of the diffraction space from a TEM. It consists of two subsequent tilt scans of the goniometric stage; one to obtain a crystal tracking file and a secon…

Intrinsic nanostructures on the (001) surface of strontium titanate at low temperatures

2020

Atomically smooth (001) surfaces of SrTiO3 cut from the high-quality single crystals at two different miscut angles 0.9 and 7.0 deg between the real flat surfaces and crystallographic planes (001) were analyzed by means of the reflection high energy electron diffraction (RHEED) method from the room down to liquid helium temperatures. The diffraction patterns typical of the RHEED geometry close to ideal for a small miscut angle and those exhibiting distinct features of the specific periodicity associated with regular steps, which form due to the larger miscut angle, are presented. The surface symmetry and energetics were shown to impose differences in lattice parameters in parallel to a surf…

Quasi-parallel precession diffraction: Alignment method for scanning transmission electron microscopes.

2018

Abstract A general method to set illuminating conditions for selectable beam convergence and probe size is presented in this work for Transmission Electron Microscopes (TEM) fitted with µs/pixel fast beam scanning control, (S)TEM, and an annular dark field detector. The case of interest of beam convergence and probe size, which enables diffraction pattern indexation, is then used as a starting point in this work to add 100 Hz precession to the beam while imaging the specimen at a fast rate and keeping the projector system in diffraction mode. The described systematic alignment method for the adjustment of beam precession on the specimen plane while scanning at fast rates is mainly based on …

Compact setup for spin-, time-, and angle-resolved photoemission spectroscopy.

2020

Review of scientific instruments 91(6), 063001 (2020). doi:10.1063/5.0004861

Development of hard x-ray photoelectron SPLEED-based spectrometer applicable for probing of buried magnetic layer valence states

2016

Abstract A novel design of high-voltage compatible polarimeter for spin-resolved hard X-ray photoelectron spectroscopy (Spin-HAXPES) went into operation at beamline BL09XU of SPring-8 in Hyogo, Japan. The detector is based on the well-established principle of electron diffraction from a W(001) single-crystal at a scattering energy of 103.5 eV. It's special feature is that it can be operated at a high negative bias potential up to 10 kV, necessary to access the HAXPES range. The polarimeter is operated behind a large hemispherical analyzer (Scienta R-4000). It was optimized for high transmission of the transfer optics. A delay-line detector (20 mm dia.) is positioned at the exit plane of the…

Essential features of the polytypic charoite-96 structure compared to charoite-90

2011

AbstractCharoite, ideally (K,Sr,Ba,Mn)15–16(Ca,Na)32[(Si70(O,OH)180)](OH,F)4·nH20, is a rock-forming mineral from the Murun massif in Yakutia, Sakha Republic, Siberia, Russia, where it occurs in a unique alkaline intrusion. Charoite occurs as four different polytypes, which are commonly intergrown in nanocrystallme fibres. We report the structure of charoite-96(a =32.11(6),b =19.77(4),c =7.23(1) Å, β = 95.85(9)°,V =4565(24) Å3, space groupP21/m),which was solvedab initioby direct methods on the basis of 2676 unique electron diffraction reflections collected by automated diffraction tomography and refined toR1/wR2=0.34/0.37. The structure of charoite-96 is related to that of the charoite-90,…

Experimental characterization of electronic, structural and optical properties of individual carbon nanotubes

2014

Molybdenum oxide nitrides of the Mo_{2}(O,N,\square)_{5}$ type : on the way to Mo_{2}O_{5}$

2017

Abstract: Blue-colored molybdenum oxide nitrides of the Mo-2(O,N,square)(5) type were synthesized by direct nitridation of commercially available molybdenum trioxide with a mixture of gaseous ammonia and oxygen. Chemical composition, crystal structure, and stability of the obtained and hitherto unknown compounds are studied extensively. The average oxidation state of +5 for molybdenum is proven by Mo K near-edge X-ray absorption spectroscopy; the magnetic behavior is in agreement with compounds exhibiting (MoO6)-O-v units. The new materials are stable up to similar to 773 K in an inert gas atmosphere. At higher temperatures, decomposition is observed. X-ray and neutron powder diffraction, e…