Long-lived NV and #8722; spin coherence in high-purity diamond membranes
N/A
77 NANOSCIENCE AND NANOTECHNOLOGY↗
Engineering topics
Gaathon, O
Publications and source records attributed to Gaathon, O.
Planar single-crystal thin-films of YAG obtained by ion implantation and thermal exfoliation: Mechanical properties
N/A
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
Twinning and Dislocation Pileups in Heavily Implanted LiNbO3
The nature of a striking pattern of extended defects formed by very high dose implantation of helium in a complex oxide, for example, ferroelectricz-cut LiNbO{sub 3}, is studied. After irradiation, a high concentration of defects is found to collect and create a network of thick prismatic planar defects, which have typical dimensions of {approx}1.5 {micro}m and 200 nm parallel and perpendicular to the z axis, respectively. This defect network and its effect on the lattice were studied using a set of x-ray and electron microscopy probes of the lattice structure and spatial variation. Optical microscopy shows that there is strong temperature dependence for forming the network; the density of these extended defects reaches a maximum value for an annealing temperature of 250 C but is fully eliminated by a temperature of 380 C. High-resolution transmission electron microscopy studies indicate that these extended defects are probably localized twinning and dislocation pileups due to plastic deformation of the lattice to relieve He-implantation-induced stress. During this deformation, He accumulates at the twin boundaries. The study also shows that the He interstitials evolve into bubbles causing high stress and resulting in a formation of thick prismatic planar defects. Finally, a mechanism is proposed for defect creation and elimination.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
Spherical Solid He Nanometer Bubbles in an Anisotropic Complex Oxide
We show, using room temperature, high-resolution electron microscopy studies, that implanted He in LiNbO{sub 3} nucleates and accumulates as bubbles. These He inclusions are at {approx} 20 GPa pressure and most probably in the solid phase. In addition, the energetically favored shape of the inclusions in their as-implanted form is spherical and not oblate; this spherical shape is due to the fact that their diameter is below a critical radius for balancing the surface and elastic energies as predicted by elastic theory. When annealed, the characteristic length scale of the He inclusions increases, forming faceted bubbles. Annealing also causes the He inclusions to migrate and accumulate into strings due to the preferred {l_brace}101{bar 4}{r_brace}-pyramidal-twinning planes.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗