EPR spectra and crystal field of hexamer rare-earth clusters in fluorites / Kazanskii SA,Ryskin AI,Nikiforov AE,Zaharov AY,Ougrumov MY,Shakurov GS // PHYSICAL REVIEW B. - 2005. - V. 72, l. 1.

ISSN/EISSN:

1098-0121 / нет данных

Type:

Article

Abstract:

Disordered fluorite-related solid solutions (AF(2))(1-x-y) (Ln(')F(3))(x) (Ln(')F(3))(y), where A=Ca, Sr, Ba; Ln(')=Er, Tm, Yb; Ln(')=Lu, Y; and x << y=0.001-0.4, were studied by both optical detection and conventional electron paramagnetic resonance (EPR) techniques. The EPR spectra of paramagnetic rare-earth ions Er3+, Tm3+, and Yb3+ in clusters of diamagnetic Y3+ and Lu3+ ions were recorded. It appears that the crystalline electric field at the sites of Ln ions in the clusters is of ``nearly{''} tetragonal symmetry and provides for high values of factors g(parallel to), approaching the theoretical limits, and small values of factors g(perpendicular to)similar to 0 in the ground states of the paramagnetic Ln ions. It was assumed that all the clusters of Ln ions in the solid solutions appear to be similar in structure to the hexameric clusters, which are the basic structural units of the homologous series of fluorite-related superstructures (AF(2))(1-y)(LnF(3))(y) with compositions y=5/m, where m is an integer in the range of 13-19. The structure of ``symmetric{''} hexameric clusters in CaF2, SrF2, and BaF2 hosts was established by computer simulation. The crystalline electric field and the spectroscopic ground-state parameters for Er3+, Tm3+, and Yb3+ ions in the hexameric clusters were calculated and found to be in agreement with the experimental data, being totally different from those known for the ``isolated{''} simple cubic and tetragonal centers in the fluorite crystals.

Author keywords:

SHORT-RANGE ORDER; ELECTRON-PARAMAGNETIC RESONANCE; CUBOCTAHEDRAL ANION CLUSTERS; DEFECT AGGREGATION; EXCESS FLUORITES; 2-LEVEL SYSTEMS; SOLID-SOLUTION; CUBIC SITES; IONS; PHASES

DOI:

10.1103/PhysRevB.72.014127

Web of Science ID:

ISI:000230889800071

Соавторы в МНС:

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Другие поля

Поле	Значение
Month	JUL
Publisher	AMERICAN PHYSICAL SOC
Address	ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA
Language	English
Article-Number	014127
Keywords-Plus	SHORT-RANGE ORDER; ELECTRON-PARAMAGNETIC RESONANCE; CUBOCTAHEDRAL ANION CLUSTERS; DEFECT AGGREGATION; EXCESS FLUORITES; 2-LEVEL SYSTEMS; SOLID-SOLUTION; CUBIC SITES; IONS; PHASES
Research-Areas	Physics
Web-of-Science-Categories	Physics, Condensed Matter
ResearcherID-Numbers	Nikiforov, Anatoliy/L-4436-2016
Number-of-Cited-References	57
Usage-Count-Last-180-days	1
Usage-Count-Since-2013	24
Journal-ISO	Phys. Rev. B
Doc-Delivery-Number	950WQ