Inhomogeneity of the intrinsic magnetic field in superconducting YBa2Cu3OX compounds as revealed by rare-earth EPR-probe

X-band electron paramagnetic resonance on doped Er3+ and Yb3+ ions in Y0.99(Yb,Er)0.01Ba2Cu3OX compounds with different oxygen contents in the wide temperature range (4-120)K have been made. In the superconducting species, the strong dependencies of the linewidth and resonance line position from the sweep direction of the applied magnetic field are revealed at the temperatures significantly below TC. The possible origins of the observed hysteresis are analyzed. Applicability of the presented EPR approach to extract information about the dynamics of the flux-line lattice and critical state parameters (critical current density, magnetic penetration depth, and characteristic spatial scale of the inhomogeneity) is discussedComment: 17 pages, 5 Figures. Renewed versio

Pulsed electron-nuclear double resonance diagnostics of Ce³⁺ emitters in scintillating garnets

© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimPulsed electron paramagnetic resonance (EPR) and pulsed electron-nuclear double resonance (ENDOR) techniques have been applied to study the environment of luminescent Ce3+ ions in garnet based scintillator powders and ceramics. The presence of aluminum and gallium isotopes with large nuclear magnetic and quadrupole moments in the nearest neighborhood of the Ce3+ ion allows for the use of the hyperfine and quadrupole interactions with these ions for determination of the unpaired electron spatial distribution and the definition of the electric field gradient at the aluminum and gallium sites. Pulsed EPR and ENDOR techniques made it possible to study the coherent properties of the Ce3+ spin system in garnet powders and ceramics, which is important for spin manipulation on Ce3+ centers

Recent researches of the copper centres in potassium tantalate single crystals

Electron paramagnetic resonance (EPR) of single. Cu(2+) ions and exchange-coupled Cu(2+)-Cu(2+) pairs in KTaO(3), KTaO(3):Li:Cu and KTaO(3):Li:Nb crystals has been analyzed in the temperature range of 300 - 1000 K. The temperature stability of the paired centers was found to be similar to that of single Cu(2+) ions. The influence of oxygen vacancies on the Cu(2+) EPR spectra was studied