Teuta Gasi

Design scheme of new tetragonal Heusler compounds for spin-transfer torque applications and its experimental realization.

Band Jahn-Teller type structural instabilities of cubic Mn(2)YZ Heusler compounds causing tetragonal distortions can be predicted by ab initio band-structure calculations. This allows for identification of new Heusler materials with tunable magnetic and structural properties that can satisfy the demands for spintronic applications, such as in spin-transfer torque-based devices.

Oligonuclear Ferrocene Amides: Mixed-Valent Peptides and Potential Redox-Switchable Foldamers

Trinuclear ferrocene tris-amides were synthesized from an Fmoc- or Boc-protected ferrocene amino acid, and hydrogen-bonded zigzag conformations were determined by NMR spectroscopy, molecular modelling, and X-ray diffraction. In these ordered secondary structures orientation of the individual amide dipole moments approximately in the same direction results in a macrodipole moment similar to that of α-helices composed of α-amino acids. Unlike ordinary α-amino acids, the building blocks in these ferrocene amides with defined secondary structure can be sequentially oxidized to mono-, di-, and trications. Singly and doubly charged mixed-valent cations were probed experimentally by Vis/NIR, paramagnetic ¹H NMR and Mössbauer spectroscopy and investigated theoretically by DFT calculations. According to the appearance of intervalence charge transfer (IVCT) bands in solution, the ferrocene/ferrocenium amides are described as Robin-Day class II mixed-valent systems. Mössbauer spectroscopy indicates trapped valences in the solid state. The secondary structure of trinuclear ferrocene tris-amides remains intact (coiled form) upon oxidation to mono- and dications according to DFT calculations, while oxidation to the trication should break the intramolecular hydrogen bonding and unfold the ferrocene peptide (uncoiled form).

Density of phonon states in superconducting FeSe as a function of temperature and pressure

The temperature and pressure dependence of the partial density of phonon states (phonon-DOS) of iron atoms in superconducting

Structural and magnetic properties of the Heusler compound Fe2MnGa

{\text{Fe}}_{1.01}\text{Se}

Exchange-spring like magnetic behavior of the tetragonal Heusler compound Mn2FeGa as a candidate for spin-transfer torque

was studied by

Controlling phase formation in solids: rational synthesis of phase separated Co@Fe2O3 heteroparticles and CoFe2O4 nanoparticles

^{57}\text{F}\text{e}

Synthesis, characterization and functionalization of nearly mono-disperse copper ferrite CuxFe3−xO4 nanoparticles

nuclear inelastic scattering. The high-energy resolution allows for a detailed observation of spectral properties. A sharpening of the optical phonon modes and shift of all spectral features toward higher energies by

Structural and magnetic properties of Fe2CoGa Heusler nanoparticles

\ensuremath{\sim}4\mathrm{%}

Resolving the phase structure of nonstoichiometric Co2FeGa Heusler nanoparticles

with decreasing temperature from 296 to 10 K was found. However, no detectable change at the tetragonal\char21{}orthorhombic phase transition around 100 K was observed. Application of a pressure of 6.7 GPa, connected with an increase in the superconducting temperature from 8 to 34 K, results in an increase in the optical phonon mode energies at 296 K by

Biferrocene Amino Acid, a Ferrocenylogoue of Ferrocene Amino Acid: Synthesis, Cross-Linking, and Redox Chemistry

\ensuremath{\sim}12\mathrm{%}