Superexchange and iron valence control by off-stoichiometry in yttrium iron garnet thin films grown by pulsed laser deposition
Abstract
Controlled off-stoichiometric single phase polycrystalline yttrium iron garnet (YIG) thin films have been grown by pulsed laser deposition, adjusting the oxygen partial pressure PO2 between 5 and 400 mTorr. Atomic stoichiometry by RBS shows an oxygen deficiency for PO2<Pstoich and iron and yttrium deficiency for PO2>Pstoich. Pstoich=30mTorr refers to films showing magnetic and structural properties of the bulk stoichiometric YIG. Curie temperature Tc and saturation magnetization 4πMs decreased for PO2<Pstoich, whereas a new part of the YIG phase diagram is explored for PO2>Pstoich: Increase of Tc (up to +10%) and of 4πMs (up to +20%) and lattice parameter compression. Microscopic interpretation is given in terms of superexchange interaction and creation and site selectivity of iron vacancies.
- Publication:
-
Journal of Applied Physics
- Pub Date:
- May 2005
- DOI:
- 10.1063/1.1860991
- Bibcode:
- 2005JAP....97jG108D
- Keywords:
-
- 75.50.Gg;
- 75.70.Ak;
- 75.30.Et;
- 68.55.Ln;
- 68.55.Jk;
- 81.05.Je;
- 68.55.Nq;
- 75.30.Kz;
- 75.60.Ej;
- 61.72.Ji;
- 79.20.Rf;
- 81.15.Fg;
- Ferrimagnetics;
- Magnetic properties of monolayers and thin films;
- Exchange and superexchange interactions;
- Defects and impurities: doping implantation distribution concentration etc.;
- Structure and morphology;
- thickness;
- crystalline orientation and texture;
- Ceramics and refractories;
- Composition and phase identification;
- Magnetic phase boundaries;
- Magnetization curves hysteresis Barkhausen and related effects;
- Point defects and defect clusters;
- Atomic molecular and ion beam impact and interactions with surfaces;
- Laser deposition