Isao Moritani

Monolayer of Ferromagnetic MnSb

By alternately depositing Mn(1 A) and Sb(60 A), epitaxially grown MnSb monolayers in between Sb layers have been prepared. At 4.2 K, the MnSb monolayers exhibit ferromagnetic behavior and the easy direction is found to be perpendicular to the film plane.

Anomalous X-ray scattering study of composition profile in Fe/Mn superlattice films

The wavelength dependence of the X-ray diffraction peak intensity in the small-angle region has been measured on two Fe/Mn superlattice films using synchrotron radiation. Peak intensities are found to be greatly enhanced at a wavelength slightly longer than the K-absorption edge of the Mn atom (1.896 AA), where the contrast in X-ray scattering power of the adjacent Fe and Mn layers becomes significantly large because of the effect of anomalous dispersion. Higher-order reflections up to the seventh are observed for (Fe(15 AA)/Mn(50 AA))40 and up to the third for (Fe(20 AA)/Mn(20 AA))100. Analysis of the peak width and intensity reveals intermixing of the atoms extending over several atom layers ( approximately 10-12 AA) at Fe/Mn interfaces and the fluctuation of the superlattice period within approximately 3-4 AA.

Ferromagnetic Resonance of Mn/Sb Multilayered Films with Artificial Superstructure

Ferromagnetic resonance (FMR) of multilayered metallic films synthesized from an insoluble combination of Fe and Mg is studied in a temperature range from 10 K to 300 K. A well defined FMR signal is observed in each sample with Fe thickness ranging from 4 A to 30 A. The observed spectra are found to be strongly dependent on the regularity of the layered structure. The resonance field exhibits an unusual shift which changes systematically as a function of the thickness as well as temperature. The origin of the shift of the resonance field is discussed in relation to the amorphous-like structure observed for the thickness less than 12 A.

Magnetic properties of MnSb/Sb superlattices

MnSb/Sb superlattice films containing ultrathin ferromagnetic MnSb layers (0.36–3.0 ML) have been investigated by magnetization measurements. Samples containing MnSb thinner than 3.0 ML show perpendicular magnetic anisotropy. Magnetization vs. temperature curves of samples with MnSb monolayers strongly depend on the external field.

Structural and magnetic properties of 3d/Sb multilayers

Abstract Structures and magnetic properties of artificially prepared multilayers consisting of Sb and a 3d metal (Cr, Mn, Fe, Co or Ni) have been investigated. Obtained structures greatly depend on the reactivity between Sb and the metal. In the most reactive combination, Mn and Sb, ferromagnetic MnSb monolayers were prepared. An influence of substrate temperature on the multilayered structure is typically shown in the case of Cr and Sb.

X-ray diffraction study of Mn/Sb multilayered films with artificial superstructures

Structures of Mn/Sb multilayered films have been investigated by X-ray diffraction. MnSb/Sb superlattice films are obtained when the nominal thicknesses are (Mn(1 AA)/Sb(50 AA))90 and (Mn(2 AA)/Sb(50 AA))90. Ultrathin layers of MnSb are formed by interfacial reaction in these samples with keeping an epitaxial orientation of (00.1)MnSb//(00.1)Sb; (11.0)MnSb//(11.0)Sb. These films have fibre texture structures with an in-plane coherence length of about 300 AA. The distribution of growth orientation is approximated by a Gaussian distribution function with a half-width of about 10 degrees . The analyses of diffraction intensities indicate that (i) the texture structure causes a monotonic reduction of peak intensity with increase of scattering vector including fundamental reflection and (ii) that layer thickness fluctuations in the range of one or two monolayers cause peak broadening and intensity reduction only for the higher-order satellite reflections. Observed satellite intensities could be reproduced by a model calculation which takes into consideration these two effects.

Thin films-preparation, structure and properties. Epitaxial growth of Mn-Sb multilayered films.

Mn-Sb積層膜の透過電子顕微鏡観察を行なった。膜厚300ÅのSb膜をトリアセチルセルロースフィルム基板上に基板温度室温で蒸着すると,粒径約500ÅのC面配向多結晶膜が得られる。このような配向性Sb膜上にMnを蒸着すると,Mnの蒸着膜厚40Åの場合にもMn原子はすべてSb原子と反応し,Sb層上にエピタキシャルに成長した金属間化合物MnSb(膜厚100Å)が生成される。

Magnetic Properties of Mn-Sb Multilayered Films

Mn-Sb multilayered films were prepared by the alternate vapor deposition method. MnSb is formed even at a substrate temperature of -100°C, demonstrating the extreme reactivity of Mn. A perfectly uniform ferromagnetic MnSb polycrystal was obtained when the Mn to Sb mole ratio was 1 : 1. When MnSb was in the equilibrium state, the most Sb-rich MnSb system compound was produced, and the reaction between Mn and Sb did not proceed beyond that point, demonstrating that it is possible to fabricate a multilayered film with a ferromagnetic ultrathin MnSb film sandwiched between Sb layers.