Bubble domains in remanence state in monocrystalline, epitaxial ferrite layers/MgMnFe/3O4

Magnetic domain structure was studied in monocrystalline, epitaxial ferrite layers of spinel structure for MgMn-ferrites using magnetic colloid technique. The layers, 6 micrometers thick, were obtained by CVD on monocrystalline MgO substrates. Layers obtained at 1550°K exhibit growth- and stress-induced anisotropy. The domain structure was studied in the demagnetized and remanence states, and on applying a static magnetic field of up to 2 KOe perpendicularly to the layer. In the remanence state, bubble domains 3+4 micrometers in diameter form a hexagonal lattice. In the demagnetized state, after AC-demagnetization, the bubbles are 1 micrometers in diameter and form a regular lattice. Both lattices are stable in magnetic fields of less than 100 Oe. The bubble mobility, measured by the ferromagnetic resonance method, is about 250 cm/Oe s.