Associated incorporation of boron, lead, and oxygen vacancies in garnets
Abstract
Local vibrational modes observed in the IR spectrum of iron garnets and noniron garnets have been identified and arise from a complex formed by a boron-oxygen group [BO3]3-, a heavy metal ion M2+, and an oxygen vacancy. The energy of the local modes is affected by the electron population of the vacancy ranging from 0 to 2, and by the exact nature of the M2+ ion, being in most cases Pb2+. This is a first spectroscopic indication of the occurrence of oxygen vacancies in iron garnets. In iron-containing garnets, the whole complex can act as a charge compensator of additional lattice defects, owing to the associated M2+ ion and oxygen vacancy, the latter having different states of ionization. From the boron spectrum observed in a particular yttrium iron garnet (YIG) sample, one may infer at least in a qualitative way the underlying position of the Fermi level. Measurements at different temperatures reveal that the donor level of the singly ionized oxygen vacancy in YIG should lie about 0.15 eV below the level of a silicon donor residing nearby. Formation of the boron-oxygen complex near the M2+ ion seems to be facilitated since it tends to compensate the expansive lattice strain induced by the heavy metal ion.
- Publication:
-
Journal of Applied Physics
- Pub Date:
- December 1979
- DOI:
- 10.1063/1.325983
- Bibcode:
- 1979JAP....50.7986A
- Keywords:
-
- Doped Crystals;
- Garnets;
- Metal Ions;
- Vacancies (Crystal Defects);
- Yttrium-Iron Garnet;
- Boron;
- Fermi Surfaces;
- Lattice Parameters;
- Lead (Metal);
- Oxygen;
- Silicon;
- Solid State Physics;
- Solid-State Physics;
- 61.70.Ey;
- 78.50.Ec;
- 71.55.Ht;
- 63.20.Pw;
- Other nonmetals;
- Localized modes