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Results of neutron scattering studies on MnTe/CdTe superlattices with ultrathin non-magnetic CdTe “barriers” are presented and compared with data from earlier studies on MnSe/ZnSe, MnTe/ZnTe, and MnSe/ZnTe multilayers with thick non-magnetic spacers. The experiments revealed two qualitatively new effects—namely, (i) the existence of pronounced interlayer magnetic correlations in the case of the CdTe thickness corresponding to two single monolayers and (ii) the coexistence of two magnetic phases that never occurred simultaneously in the previously studied systems.

Les spectres de diffraction de neutrons des couches monocristallines de type zinc-Blende revelent l'etablissement d'un ordre antiferromagnetique de type-III (AFM-III) pour x=0.7 et 0.75 a une temperature de Neel precise. La phase (AFM-III) presente un ordre a grande distance, avec des longueurs de correlation d'environ 400 A, et la transition est du second ordre. Leger contraste avec des etudes anterieures des semiconducteurs magnetiques A 1-x III Mn x B VI dilues en volume, dans lesquelles seules les correlations AFM-III d'ordre a courte distance sont observees

Inelastic neutron scattering studies of AII1−xMxBVI diluted magnetic semiconductor (DMS) alloys with low and high concentations of the magnetic component (M) are reviewed. Measurements of inelastic scattering from isolated pairs of magnetic ions makes possible a direct determination of the ion–ion exchange parameters. This method has been used for JNN determination in Zn1−xMnxB (B=S, Se, Te) and Zn1−xCoxB DMS alloy families. Inelastic scattering experiments on DMS alloys with high magnetic ion concentrations (Zn1−xMnxTe and Cd1−xMnxTe with x=0.4–0.7) reveal that at low T the magnetic excitation spectra of these systems are dominated by magnonlike modes despite the absence of long‐range magnetic order. A theoretical description of these excitations can be obtained using the numerical method developed by Ching and Huber. The model results reproduce remarkably well the dispersion and the line‐shape characteristics of the excitation modes seen in the experiments.

We report neutron diffraction studies of Zn 1- x Mn x Te epitaxial layers for x =0.71, 0.84, 0.94 and 1 (pure MnTe). Molecular beam epitaxy (MBE) was used to grow the crystals on a GaAs (100) surface, resulting in zinc blende (ZB) crystallographic structure of the epilayers for all compositions. The film thickness were in the micrometer range, and could be characterized as bulk-like in terms of the strain and magnetic properties. The quality of the crystal was remarkably good, giving an indication that the NiAs form of MnTe grown by conventional techniques may be metastable at room temperature.

Inelastic neutron scattering measurements of polycrystalline NiSi2 are compared to Raman scattering spectra of the corresponding amorphous phase. Broad similarities are observed between the two Raman bands and more detailed features of the crystalline spectra. The results are consistent with similar short range order in the amorphous and crystalline phase.

Spectroscopic ellipsometry was used to determine the pseudodielectric constants of thin film sputtered crystalline nickel and the concentrated amorphous Ni 0.95 Tb 0.05 alloy. The variation in ϵ 2 ( ω )/ λ , which indicates the matrix element weighted joint density of states, is found to be relatively similar for both crystalline and amorphous systems. This is interpreted in terms of related short-range order and similar d band states in both these materials.