(H sup minus Ca sup + ) sup 0 defect in thermochemically reduced CaO: A static and dynamical EPR study

Journal Article · Mon Oct 15 00:00:00 EDT 1990 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.42.7604· OSTI ID:6288261

Orera, V M; Sanjuan, M L ^[1]; Chen, Y ^[2]

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1. Instituto de Ciencia de los Materiales de Aragon, Consejo Superior de Investigaciones Cientificas, Universidad de Zaragoza, Zaragoza (Spain)
2. Solid State Division, Oak Ridge National Laboratory, Oak Ridge, TN (USA)

The H{sup {minus}}Ca{sup +}{sup 0} defect has been produced in thermochemically reduced CaO crystals and studied by electron paramagnetic resonance (EPR). These defects act as low-temperature traps for electrons released during the photoconversion of F{r arrow} ital F{sup +} centers. The defects are stable up to 80 K. Below 20 K the spectrum corresponds to the static situation, described by tetragonal symmetry with g{sub {parallel}}=2.0003(2) and g{sub {perpendicular}}=1.9996(2), A{sub {parallel}}=41.2{plus minus}0.2 MHz and A{sub {perpendicular}}=21.4{plus minus}0.2 MHz. The nuclear Zeeman term and the hyperfine interaction are of similar strength, and the spectrum shows a strong forbidden'' lines pattern. Above 20 K electron hopping occurs among the six equivalent orientations. Using the line-shape method based on the stochastic Liouville equation, we have studied the evolution of the EPR spectrum with temperature. The motion is thermally activated with a small activation energy {approx}0.007 eV. A polaronlike behavior is proposed for the defect.

• DOE Contract Number: AC05-84OR21400
• OSTI ID: 6288261
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 42:12; ISSN PRBMD; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
ACTIVATION ENERGY
ALKALINE EARTH METAL COMPOUNDS
ANIONS
CALCIUM COMPOUNDS
CALCIUM IONS
CALCIUM OXIDES
CHALCOGENIDES
CHARGED PARTICLES
COLOR CENTERS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
ELECTRON SPIN RESONANCE
ENERGY
F CENTERS
HYDROGEN IONS
HYDROGEN IONS 1 MINUS
IONS
LOW TEMPERATURE
LUMINESCENCE
MAGNESIUM COMPOUNDS
MAGNESIUM OXIDES
MAGNETIC RESONANCE
OXIDES
OXYGEN COMPOUNDS
PHOSPHORESCENCE
POINT DEFECTS
RESONANCE
TEMPERATURE DEPENDENCE
TRAPS
VACANCIES
VERY LOW TEMPERATURE