Document Type

Article

Publication Date

10-2015

Abstract

Singly ionized oxygen vacancies are produced in LiAlO2 crystals by direct displacement events during a neutron irradiation. These vacancies, with one trapped electron, are referred to as V+O centers. They are identified and characterized using electron paramagnetic resonance (EPR) and optical absorption. The EPR spectrum from the V+O centers is best monitored near 100 K with low microwave power. When the magnetic field is along the [001] direction, this spectrum has a g value of 2.0030 and well-resolved hyperfine interactions of 310 and 240 MHz with the two 27Al nuclei that are adjacent to the oxygen vacancy. A second EPR spectrum, also showing hyperfine interactions with two 27Al nuclei, is attributed to a metastable state of the V+O center. An optical absorption band peaking near 238 nm is assigned to V+O centers. Bleaching light from a Hg lamp converts a portion of the V+O centers to V0O centers (these latter centers are oxygen vacancies with two trapped electrons). The V0O centers have an absorption band peaking near 272 nm, a photoluminescence band peaking near 416 nm, and a photoluminescence excitation band peaking near 277 nm. Besides the oxygen-vacancy EPR spectra, a holelike spectrum with a resolved, but smaller, hyperfine interaction with one 27Al nucleus is present in LiAlO2 after the neutron irradiation. This spectrum is tentatively assigned to doubly ionized aluminum vacancies.

Comments

This record sources the open access CHORUS-furnished accepted manuscript (post-print) version of the article. A 12-month embargo was observed for this posting in accordance with the publisher and the research funding body.

The publisher version of record is a subscription-access article, appearing as cited below in volume 92 of Physical Review B, hosted at APS. Readers outside of AFIT will need to access the article through their own digital subscription to that periodical. AFIT readers can reach the final article through AFIT Off-Campus Access.

DOI

10.1103/PhysRevB.92.144108

Source Publication

Physical Review B (Condensed Matter and Materials Physics)

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