The magnetization process and domain structure of free layers in as deposited and annealed magnetic tunnel junctions (MTJ) of Si/Ta/Cu/Ta/NiFe/Cu/IrMn(10)/CoFe(2.5)/Al-O(1.5)/CoFe(2.5)/NiFe(t)/Ta, where t = 10, 30 and 100 nm, were investigated by Kerr microscopy, R-VSM and MOKE magnetometers. Different types of domain patterns observed in free layers (CoFe(2.5)/NiFe(t)) depending on the mutual relation between interlayer coupling energy and free layer magnetostatic energy. For as deposited samples fuzzy domains with fine irregular "patches" pattern, typical for weak interlayer coupling, are observed. Annealed MTJs, however, are characterized by large domains superimposed by crossed stripes, which led to the blocking of coherent rotation of magnetization.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics