The irradiation effect of 1 MeV C+ on the interface and magnetic anisotropy of epitaxial Cu/Ni system with a perpendicular magnetic anisotropy was investigated by using magneto-optical Kerr effects, grazing incident diffraction and X-ray reflectivity. The magnetic easy-axis was altered from the direction along the surface normal to in-plane and the strain in the Ni layer was relaxed after ion irradiation. Though the interface between the top Cu layer and the Ni layer becomes rough, the contrast of electron densities of Cu and Ni layer increases and the grain-growth occurs during ion irradiation. These phenomena arise from thermo-chemical driving force, i.e. heat of formation, which may be a crucial factor in determining the interface shape in the case of indirect energy transfer mechanism. Therefore, the change of the magnetic anisotropy of the Ni/Cu system after ion irradiation is not due to the formation of the intermixed layer at the interface. The ion irradiation effects on the grain-growth and enhancement of the electronic contrast between Ni and Cu are explained by the interfacial atomic movement caused by thermo-chemical driving force.
Bibliographical noteFunding Information:
This research was partly supported by R&D Program for NT-IT Fusion Strategy of Advanced Technologies, Basic Research Program of the Korea Science & Engineering Foundation Grant no. R01-2004-000-10715-0, the Mid- and Long-term Nuclear R&D Program, eSSC at POSTECH, Nano analysis project and Brain Korea 21. Measurements at the PLS were supported through the X-ray/particle-beam Nano-characterization Program by MOST and POSTECH Foundation.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics