Various mechanisms leading to coercivity phenomena in near-perfect single crystalline epitaxial magnetic garnet layers with 180° Bloch walls were investigated. It was shown that the contributions from the statistical fluctuations of exchange and anisotropy energies are negligibly small. Due to the very low dislocation density ( <10 cm-2) their summarized effect on the coercive force (Hc) is very small, too. Non-magnetic inclusions have a very low volume fraction, their effect is in the 10-4 Oe range. The transition layer between substrate and epitaxy can cause significant coercivity increase due to magnetostrictive stresses. The as-grown surface relief of the crystals has a definite dependence on composition, giving a surface contribution to Hc up to some Oe. Coercivity changes caused by chemical and mechanical treatment of the surface are discussed.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics