Solid-state reaction in Ti/Ni multilayered films studied by using magneto-optical spectroscopy

A comparative study of the solid-state reaction (SSR) in a series of Ti/Ni multilayered films (MLFs) with bilayer periods of 0.65-22.2 nm and a consta nt Ti to Ni sublayer thickness ratio was performed by using experimental an d computer-simulated magneto-optical (MO) spectroscopy based on different m odels of MLFs, as well as x-ray diffraction (XRD). The spectral and sublaye r-thickness dependences of the MO properties of the Ti/Ni MLFs were explain ed on the basis of the electromagnetic theory. The existence of a threshold nominal Ni-sublayer thickness of about 3 nm for the as-deposited Ti/Ni MLF to observe of the equatorial Kerr effect was explained by a solid-state re action which formed nonmagnetic alloyed regions between pure components dur ing the MLF deposition. The SSR in the Ti/Ni MLFs, which was caused by the low temperature annealing, led to the formation of an amorphous Ti-Ni alloy and took place mainly in the Ti/Ni MLFs with "thick" sublayers. For the ca se of Ti/Ni MLFs, the MO approach turned out to be more sensitive in determ ining the thickness of the reacted zone, while XRD was more useful for the structural analysis. It was also suggested that very thin non-reacted Ni su blayers had different MO properties from those of the bulk.