An empirical relationship describing the radial dependence of the nondipole part of the anisotropic constant for the ligand hyperfine interaction in alkaline-earth fluorides is proposed. This relationship is used for calculating the distances between the magnetic ion and the fluorine ions involved in its nearest environment. The results of the calculations are in good agreement with the values obtained by other methods for both cubic and tetragonal fluorine centers in these crystals. The distances from the magnetic ion to different groups of nonequivalent fluorine ions of the nearest environment in Yb 3+ trigonal centers of SrF 2 and BaF 2 are determined. It is found that the Yb 3+ ion is slightly displaced along the trigonal axis away from the compensating fluorine ion.

A method is suggested for estimating local lattice distortions near a paramagnetic center by using the parameters determined from experimental tensors of the ligand hyperfine interaction with surrounding nuclei through the use of a simple mathematical procedure. In general, a tensor with nine independent components can be unambiguously reduced to nine independent parameters characterizing the hyperfine interaction: the isotropic part, deviations from the symmetric and axially symmetric form, the axially symmetric component (containing dipole and pseudodipole contributions), and the angles defining the bond direction. Under certain physical assumptions, these parameters are used to estimate distortions of the first and second coordination shells of Ce 3+ in the homologous series CaF 2 , SrF 2 , and BaF 2 .

The ligand hyperfine interaction (HFI) of Gd3+ ions in α-LiIO3 single crystals is studied by the method of rf discrete saturation, and the tensor components of ligand HFI are determined. The model of a paramagnetic center is proposed on the basis of the analysis of the obtained results, and the mechanism of lattice distortion is discussed.

The absorption spectrum and the Stark structure are measured for the first time at the temperature T = 300 K for high-lying F-3(4), F-3(3), F-3(2), (1)G(4), D-1(2), I-1(6), P-3(0), P-3(1), P-3(2) multiplets of Tm3+ ions in the YAG : Tm-3 laser system with a concentration of 2, 5, 10, 15, and 80% and for I-1(6), P-3(0), P-3(1), and P-3(2) multiplets in the YLiF4 : Tm3+ matrix with a concentration of 1%. It is demonstrated that, in the pulse-periodic regime of excitation, transmission and absorption coefficients of laser crystals depend on the relation of the time interval between the pulses (Delta T) and the lifetime tau of the metastable activator level if Delta T much less than tau. The investigation of absorption spectra of crystals with different concentrations of Tm3+ has shown that, for excitation rates of active centers equal to 10(7) and 10(5) s(-1), two photons are sequentially absorbed through the H-3(6) --> F-3(3) --> D-1(2) and H-3(6) --> (1)G(4) --> P-3(2) schemes. Analysis of the transmission coefficient I/I-0 of the YAG : Tm3+ (2%) crystal as a function of the laser intensity of a free-running ruby laser reveals the appearance of induced emission from the D-1(2) level in the process of excitation.

An EPR study of the self-trapped hole center (VKA center) in Na-doped single-crystal CaF2 is reported. A five-component hyperfine-interaction tensor was used for the first time to describe EPR spectra adequately. The parameters of the electron spin Hamiltonian of the VKA center, the tensors of ligand hyperfine interaction with all nearest-neighbor nuclei, and constants of quadrupole interaction with the Na nucleus have been determined. The structure of the center has been unambiguously established from the results obtained, and the mechanisms of its formation are discussed.

The effect of a pulse magnetic field on formation of the single-pulse echo signal in some magnetic materials has been studied. The signals of nuclear-spin echo formed by the combined action of radio frequency and magnetic pulses have been observed. The duration of the magnetic pulse was only limited by the length of the radio frequency pulse. The echo signal formed by the two magnetic pulses, the edges of a long magnetic pulse, and other situations that allowed us to reproduce the analogue of multipulse action, were observed as well.

A Fouier-transformed analog of the pulsed method of rf discrete saturation is proposed.

Памяти Георгия Викторовича Скроцкого, Ацаркин В.А., Боровик-Романов А.С., Буишвили Л.Л., Валиев К.А., Вонсовский С.В., Гуревич А.Г., Карлов Н.В., Кессених А.В., Кокин А.А., Кочелаев Б.И., Провоторов Б.Н., Прохоров А.М., Санадзе Т.И., Туров Е.А.

physica status solidi (b)Volume 158, Issue 2 p. K195-K196 Short Note EPR and RFDS Study of Gd3+ in α-LiIO3 Single Crystals D. L. Dzhaparidze, D. L. Dzhaparidze Department of Physics, Tbilisi State University Search for more papers by this authorS. V. Alchangyan, S. V. Alchangyan Department of Physics, Tbilisi State University Search for more papers by this authorD. M. Daraselia, D. M. Daraselia Department of Physics, Tbilisi State University Search for more papers by this authorT. I. Sanadze, T. I. Sanadze Department of Physics, Tbilisi State University Search for more papers by this author D. L. Dzhaparidze, D. L. Dzhaparidze Department of Physics, Tbilisi State University Search for more papers by this authorS. V. Alchangyan, S. V. Alchangyan Department of Physics, Tbilisi State University Search for more papers by this authorD. M. Daraselia, D. M. Daraselia Department of Physics, Tbilisi State University Search for more papers by this authorT. I. Sanadze, T. I. Sanadze Department of Physics, Tbilisi State University Search for more papers by this author First published: 1 April 1990 https://doi.org/10.1002/pssb.2221580257Citations: 1 Prospekt Chavchavadze 3, SU-380028 Tbilisi, USSR. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat No abstract is available for this article. References 1 D. L. Yaparidze, S. V. Alchangyan, D. M. Daraselia, and T. I. Sanadze, Fiz. tverd. Tela 31, 268 (1989). 2 G. R. Khutsishvili and T. I. Sanadze, Proc. XVIII Congr. AMPERE 1, 17 (1977). 3 D. M. Daraselia and A. Bräuer, phys. stat. sol. (b) 109, 223 (1982). Citing Literature Volume158, Issue21 April 1990Pages K195-K196 ReferencesRelatedInformation