M. Doi

Solid-state amorphization in palladium/titanium multilayer films during sputter deposition and postdeposition annealing

Microstructures in Pd/Ti multilayer films have been investigated using X-ray diffraction, Auger electron spectroscopy and cross-sectional transmission electron microscopy. Multilayer films consisting of crystallites with preferred orientations in Pd and Ti layers after deposition exhibit crystalline-to-amorphous phase transition during thermal annealing at 573–623 K. This solid-state amorphization reaction is discussed in terms of a metastable phase diagram calculated for this system.

Magnetoresistance and structure of Fe/Cu multilayers

Abstract The MR effect in Fe/Cu multilayers prepared by the IBS method under various deposition conditions has been investigated from the standpoint of the film structure. We find that the GMR of Fe/Cu is closely related to the preferred orientation of [001] and the expansion of in-plane interplanar lattice spacing of Fe.

Magnetic properties of fcc‐Fe multilayer (invited) (abstract)

Recently, magnetic properties of fcc‐Fe ultrathin films have been extensively investigated. The results, however, are complicated and inconsistent with one another. These are antiferromagnetism, ferromagnetism, different Fe magnetic moment for different atomic sites in film or a rearrangement of surface Fe atoms etc. In this article the recent results for fcc‐Fe multilayers will be reported and discussed to obtain a unified picture for magnetism of fcc‐Fe ultrathin films. Epitaxially grown multilayers of fcc‐Fe with Cu or Cu‐M (M=Au,Ni) spacer on Cu(001) and Cu(111) substrates were prepared by molecular beam epitaxy method. The Cu‐M spacer was adopted to change the mean interatomic distance between Fe atoms at interfaces by changing the composition of M (=Au,Ni), where Au was used to increase the distance and Ni to decrease it. Fe layers on a pure Cu spacer were fcc and the magnetic moment was at most 2.0μB. Fe layers on a Cu‐Au spacer, however, were fct with c/a<1 and those on Cu‐Ni with c/a≳1, where a i...

Magnetic properties and polar Kerr effect of [γ-Fe/Cu] multilayers

Abstract Magnetic properties and magneto optical polar Kerr effect of [γ-Fe/Cu] multilayers grown epitaxially by MBE method have been investigated. The occurrence of the ferromagnetism, the tetragonal distortion and the perpendicular anisotropy of γ-Fe in [γ-Fe/Cu] multilayers is discussed. The critical thickness is considered to be 2 ML Fe at interface with Cu layer. In the polar Kerr effect, the new sub-valleys of Kerr rotation and the related anomaly of Kerr ellipticity in the Kerr spectra as a function of photon energy have been observed at low temperatures. The quantum well states effect depending on the exchange splitting of the d-band has been discussed as a possible origin of the anomaly.

Microstructure of Fe/Cu (Au) artificial superlattice

Microstructures of artificial superlattices of fcc-Fe/Cu (Au) having different magnetic properties have been studied by means of cross-sectional transmission electron microscopy (TEM). The superlattice made on a very flat substrate whose saturation magnetization was about 25 emu/g Fe constituted a flat film with the step of < 1 nm at the interface between Fe and Cu (Au). On the other hand, the film on a slightly rough substrate having a larger magnetization showed a wavy contrast with a width of several hundred nanometers and a height of several tens of nanometers reflecting the geometry of the substrate. At the interfaces a wavy contrast with a width of several tens of nanometers and a height of several nanometers was observed. The difference of the microstructures in these two samples was mainly this wavy geometry at the interface inside the superlattice. The observed microstructure must play an important role influencing the magnetic property of the superlattice.