Improved ferroelectric performance of La:Hf0.5Zr0.5O2 thin films

This work was supported by Russian Science Foundation (Project. No 18-19-00527)

Leakage Currents Mechanism in Thin Films of Ferroelectric Hf 0.5 Zr 0.5 O 2

We study the charge transport mechanism in ferroelectric Hf 0.5 Zr 0.5 O 2 thin films. Transport properties of the leakage currents in Hf 0.5 Zr 0.5 O 2 are described by phonon-assisted tunneling between traps. Comparison with transport properties of amorphous Hf 0.5 Zr 0.5 O 2 demonstrates that the transport mechanism does not depend on the crystal structure. The thermal trap energy of 1.25 eV and optical trap energy of 2.5 eV in Hf 0.5 Zr 0.5 O 2 were determined based on comparison of experimentally measured data on transport with simulations within phonon-assisted tunneling between traps in dielectric films. We found that the trap density in ferroelectric Hf 0.5 Zr 0.5 O 2 is slightly less that one in amorphous Hf 0.5 Zr 0.5 O 2 . A hypothesis that oxygen vacancies are responsible for the charge transport in Hf 0.5 Zr 0.5 O 2 is confirmed by electronic structure ab initio simulation

Interaction of Nitrogen-Vacancy Centers in Diamond with a Dense Ensemble of Carbon-13

The nitrogen-vacancy center in diamond attracts a lot of attention in sensing applications, mainly for temperature, magnetic field, and rotation measurements. Nuclear spins of carbon-13 surrounding the nitrogen-vacancy center can be used as a memory or sensing element. In the current work, a diamond plate with a relatively large concentration of carbon-13 was synthesized and examined. The spectrum of optically detected magnetic resonance was recorded and analyzed in a magnetic field range of 5-200 G. A strain-independent measurement technique of carbon-13 isotope concentration based on the analysis of magnetic resonance spectra was developed. Additionally, narrow features in the spectrum were detected and understood

Atomic-level observation with three-dimensional atom probe of the solute behaviour in neutron-, ion- or electron-irradiated ferritic alloys

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On the nature of changes in the optical characterization produced in sapphire on its irradiation with a pulsed powerful stream of hydrogen ions

Changes in the optical characteristics in synthetic sapphire specimens produced by microsecond pulse irradiation with a stream of hydrogen ions of energies ranging up to tens keV have been observed. Data on decrease in the optical reflection, measured within the wavelength range of 200 900 nm, are presented. This characterization is compared with the data received by optical and atomic force microscopy as well as by lattice structure analysis performed with X-rays. The measurements indicate that the changes of optical parameters are not a consequence of absorption increase and/or sapphire decomposition. They result from modifications of the morphology and structure of surface layer of the sapphire samples, induced by irradiation

Stopping power of proton beams in a weakly nonideal xenon plasma

NIMExperimental equipment for the investigations of stopping power of proton beam in explosively driven plasma is described. A 3 MeV 60 mu s duration proton beam pulses delivered by 148.5 MHz ISTRA-36 RFQ linac at ITEP and compact metallic vacuum pumped chamber for explosions up to 150 g TNT were the main unit of this set-up. Differential pumping and fast valves proved to be sufficient for the protection of high vacuum beam line from the high pressure detonation products. Compact explosively driven cumulative shack tubes were worked out to generate uniform plasma slug behind powerful shock waves with the velocities of 10 km/s at the initial pressure of Xenon 50-200 kPa. Plasma parameters were: pressure 15-100 NIPa, electron concentration 1E+19 - 1E+20 1/cc, nonideality parameter 0.2-0.5. Stopping pourer of proton beam was defined by the displacement of the position of the spot image of the beam on the scintillator screen after it's passing through the analyzing magnet and by time of flight method. The measured values of proton beam energy losses were 100-300 keV in dependence on plasma parameters. Comparison of the experimental data with the theoretical models was carried out