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The paper presents correlation study on a series of Fe1-xAlx alloy samples prepared by arc melting. All the samples show crystalline structure, irrespective of the Al content and are textured mainly along (110) direction. The particle size decreases rapidly with x particularly after x > 0.3. The corresponding magnetic measurements were obtained at room temperature using a VSM, with a maximum applied field of 14 kOe. The results show that the ferromagnetic state of the samples disappears with x, and becomes paramagnetic for alloys with x ≥ 0.4. It is also found that coercivity (Hc) and resistivity increase with x. The results were interpreted in terms of continuous change in their electronic structure i.e. overlap of the electron wave functions of the magnetic atoms with the Al electron wave function.
Materials with a high on-off resistance ratio could become the basis for resistive random-access memory (RRAM). It is assumed that one of RRAM types can be based on hybrid organic-inorganic systems, while particular attention is focused on hybrid systems consisting of metal nanoparticles (NP) embedded in organic matrix (OM). In this investigation we created and studied the hybrid organic-inorganic systems made of metal (Ag) nanoparticles embedded in organic semiconductor material CuPc. The LEED patterns and NEXAFS data demonstrate that the CuPc films deposited on Au(001) substrate are highly ordered and molecular planes lie parallel to the gold surface. The metal atoms were deposited on the outer surface of the organic molecular film and self-assembled into nanoparticles due to surface and bulk diffusion. The properties of nano-composite materials seem to be significantly dependent on the microstructure, i.e. the size, concentration, bulk- and size-distribution of nanoparticles; therefore we have studied by high resolution transmission electron microscopy the evolution of morphology of nano-composite films as a function of nominal metal deposition. The filled and empty electronic states of the hybrid organic-inorganic systems, energy level alignment at interfaces formed between metal nanoparticles and the organic semiconductor CuPc as well as the chemical interaction at the NP/OM interface were studied by UPS, XPS and NEXAFS methods.
This paper reviews the basic properties of the SiGe alloy, presents some
new results on its electronic and optical properties, and discusses the
approach that has been followed to model quantum wells containing SiGe layers
for applications in quantum cascade lasers. The shape of the confining
potential, the subband energies and their eigen envelope wave functions are
calculated by solving a one-dimensional Schr?dinger equation. The calculations
of optical parameters are used to optimize the Si/SiGe quantum cascade
structures. Our results are found to be in good agreement with other calculations.