STRUCTURAL AND MAGNETIC-PROPERTIES OF EPITAXIAL NI80FE20 THIN-FILMS ON CU SI/

Single-crystal films of permalloy (Ni80F20) were grown on Cu(001) seed layers oriented epitaxially with Si(001). The microstructural propert ies were measured using in-situ reflection high-energy electron diffra ction, and ex-situ transmission electron microscopy, x-ray diffraction , and atomic force microscopy, whereas the magnetic properties were pr obed using in-situ magneto-optic Kerr effect and ex-situ vibrating sam ple magnetometry. Anisotropic magnetoresistance and resistivity for so me of the samples were also measured. The coercivity for thinner (less than or equal to 5 nm) Ni80Fe20 was significantly higher (10-20 Oerst eds) than polycrystalline films deposited on SiO2/Si, and was also hig her than films deposited on lattice-matched CuxNi1-x alloys. These mag netic properties were explained using a theoretical model involving in teraction of domain walls with defects such as misfit dislocations and coherent islands, due to the mismatch between Ni80Fe20 and Cu.