Average and Local Crystal Structure of β-Er:Yb:NaYF4 Upconverting Nanocrystals Probed by X-ray Total Scattering

2017 ◽  
Vol 29 (15) ◽  
pp. 6289-6297 ◽  
Author(s):  
S. Sameera Perera ◽  
Dinesh K. Amarasinghe ◽  
K. Tauni Dissanayake ◽  
Federico A. Rabuffetti
2019 ◽  
Vol 33 (33) ◽  
pp. 1950410 ◽  
Author(s):  
Ahmad S. Masadeh ◽  
Moneeb T. M. Shatnawi ◽  
Ghosoun Adawi ◽  
Yang Ren

The crystal structure of zinc metal deviates from the ideal hexagonal close packing structure by a significantly increased axial ratio (c/a). The local atomic structure of zinc metal is investigated using the total scattering atomic pair distribution function (PDF) analysis based on X-ray powder diffraction data collected at ambient conditions. The X-ray total scattering PDF analysis confirms that the crystal structure of zinc can be described in terms of wurtzite structure, but with an anomalously atomic displacement parameters [Formula: see text], indicating a significant displacement disorder along the [Formula: see text]-axis. For the long [Formula: see text]-range PDF refinements, the thermal motion of zinc shows a notable anisotropy as expressed by the ratio [Formula: see text]/[Formula: see text] of 2.5 at ambient conditions. This average distortion level along the [Formula: see text]-axis, was not reflected locally for the features below 5.0 Å as it fits the high [Formula: see text] region. Based on PDF refinements over different [Formula: see text]-ranges, we measure an interesting increase of the [Formula: see text] value with decreasing the [Formula: see text]-range of the refinement. This suggests that the local structure features in zinc metal differ from the average structure ones.


2018 ◽  
Vol 20 (47) ◽  
pp. 29817-29825 ◽  
Author(s):  
Padmalochan Panda ◽  
Nanda Gopala Krishna ◽  
Parasmani Rajput ◽  
R. Ramaseshan

In this article, we predominantly report the investigation of the local crystal structure around a Ti dopant by X-ray absorption spectroscopy (XAS) and the nano-mechanical properties of co-sputtered Al1−xTixN (x = 0 to 4%) thin films.


ACS Nano ◽  
2019 ◽  
Vol 13 (12) ◽  
pp. 14294-14307 ◽  
Author(s):  
Federica Bertolotti ◽  
Georgian Nedelcu ◽  
Anna Vivani ◽  
Antonio Cervellino ◽  
Norberto Masciocchi ◽  
...  

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Brett Leedahl ◽  
Martin Sundermann ◽  
Andrea Amorese ◽  
Andrea Severing ◽  
Hlynur Gretarsson ◽  
...  

AbstractThe one-dimensional cobaltate Ca$${}_{3}$$3Co$${}_{2}$$2O$${}_{6}$$6 is an intriguing material having an unconventional magnetic structure, displaying quantum tunneling phenomena in its magnetization. Using a newly developed experimental method, $$s$$s-core-level non-resonant inelastic x-ray scattering ($$s$$s-NIXS), we were able to image the atomic Co $$3d$$3d orbital that is responsible for the Ising magnetism in this system. We can directly observe that corrections to the commonly accepted ideal prismatic trigonal crystal field scheme occur in Ca$${}_{3}$$3Co$${}_{2}$$2O$${}_{6}$$6, and it is the complex $${d}_{2}$$d2 orbital occupied by the sixth electron at the high-spin Co$${}_{\,\text{trig}\,}^{3+}$$trig3+ ($${d}^{6}$$d6) sites that generates the Ising-like behavior. The ability to directly relate the orbital occupation with the local crystal structure is essential to model the magnetic properties of this system.


2015 ◽  
Vol 71 (a1) ◽  
pp. s90-s90
Author(s):  
Antonietta Guagliardi ◽  
Federica Bertolotti ◽  
Dmitry Dirin ◽  
Maria Ibáñez ◽  
Maksym Kovalenko ◽  
...  

2018 ◽  
Vol 20 (18) ◽  
pp. 13084-13091 ◽  
Author(s):  
Padmalochan Panda ◽  
R. Ramaseshan ◽  
Madhusmita Sahoo ◽  
Nanda Gopala Krishna ◽  
A. K. Yadav ◽  
...  

This article reports the detailed X-ray absorption spectroscopy (XAS) study of Al1−xCrxN (x = 4, 6, 11%) thin films synthesized by the reactive magnetron co-sputtering technique.


Author(s):  
H.-J. Cantow ◽  
H. Hillebrecht ◽  
S. Magonov ◽  
H. W. Rotter ◽  
G. Thiele

From X-ray analysis, the conclusions are drawn from averaged molecular informations. Thus, limitations are caused when analyzing systems whose symmetry is reduced due to interatomic interactions. In contrast, scanning tunneling microscopy (STM) directly images atomic scale surface electron density distribution, with a resolution up to fractions of Angstrom units. The crucial point is the correlation between the electron density distribution and the localization of individual atoms, which is reasonable in many cases. Thus, the use of STM images for crystal structure determination may be permitted. We tried to apply RuCl3 - a layered material with semiconductive properties - for such STM studies. From the X-ray analysis it has been assumed that α-form of this compound crystallizes in the monoclinic space group C2/m (AICI3 type). The chlorine atoms form an almost undistorted cubic closed package while Ru occupies 2/3 of the octahedral holes in every second layer building up a plane hexagon net (graphite net). Idealizing the arrangement of the chlorines a hexagonal symmetry would be expected. X-ray structure determination of isotypic compounds e.g. IrBr3 leads only to averaged positions of the metal atoms as there exist extended stacking faults of the metal layers.


Sign in / Sign up

Export Citation Format

Share Document