0000000000124432
AUTHOR
Reinhard K. Kremer
First-principles comparative study of perfect and defective CsPbX3 (X = Br, I) crystals
We thank R. Merkle for numerous fruitful discussions and G. Siegle for experimental assistance. This study was partly supported by the M-ERA-NET project SunToChem (EK). Calculations were performed using computational facilities of St. Petersburg State University and Max Planck Institute for Solid State Research. Open Access funding provided by the Max Planck Society.
Epitaxial growth and properties of (001)-oriented TbBaCo2O6−δ films
Thin epitaxial films of TbBaCo2O6−δ cobaltites have been synthesized using pulsed laser deposition. It was found that the film properties are extremely sensitive to the oxygen pressure during deposition, temperature of the substrate, and the cooling rate. Growth parameters were optimized for δ≈0.5 films with ordered Tb and Ba ions, as well as oxygen vacancies. The properties of these c-axis oriented films are similar to bulk TbBaCo2O5.5: they show a metal-insulator phase transition at TMI≈350 K, ferromagnetic order below TC=285 K, and antiferromagnetism at T<Ti≈230 K.
TaNi 2 .05Te 3 , eine Verbindung mit “aufgefüllter” TaFe 1+ x Te 3 ‐Struktur
TaNi2.05Te3, a Novel Telluride with “Stuffed” TaFe1+xTe3 Structure The novel metal-rich layer compound TaNi2.05Te3 was synthesized from the elements. Its structure contains TaNi2Te3 layers which are interconnected by Ni atoms on partially occupied tetragonal-pyramidal sites located between the layers. The title compound and the related telluride TaFe1.14Te3 form a pair of compounds differing only in the occupation or nonoccupation of one 3d-material atom site. Therefore, the structure of TaNi2.05Te3, which is stabilized by interstial Ni atoms, can be regarded as a “stuffed” TaFe1.14Te3 type. Pairs of compounds with a similar structural relationship seem to be of general importance in early …
Giant negative magnetoresistance in GdI2
Abstract GdI 2 is a layered d 1 compound which is isostructural with and nominally isoelectronic to the superconductors 2H–TaS 2 and 2H–NbSe 2 . GdI 2 orders ferromagnetically at 276(2) K and displays large negative magnetoresistance ∼70% at 7 T close to room temperature. At 10 K the saturation magnetization is 7.33(5) μ B in good agreement with the value predicted from spin polarized band structure calculations.
Giant Negative Magnetoresistance in GdI2: Prediction and Realization
The electronic structure of the layered d1 compound GdI2 has been examined systematically in view of its relation to other layered d1 systems including superconducting and isostructural 2H-TaS2 and 2H-NbSe2. A van Hove type instability is evident in suitable representations of the Fermi surface. The presence of the half-filled and magnetic 4f level should preclude the possibility of superconductivity. Instead GdI2 orders ferromagnetically at 290(5) K and displays large negative magnetoresistance ≈70% at 7 T close to room temperature. This finding provides support to the idea that materials can be searched rationally for interesting properties through high level electronic structure calculat…