Transport properties and the large anisotropic magnetoresistance of CuxNbS2 single crystals
The transport properties of CuxNbS2 (x = 0.09, 0.44 and 0.55) single crystals were systematically studied. The in-plane and out-of-plane resistivities decrease with increasing Cu content, and a transition with hysteresis shows up for the crystals with x = 0.44 and 0.55. The thermopower and Hall coefficient of CuxNbS2 show opposite signs, indicating that there are two kinds of carriers in this system. The angular dependences of the in-plane magnetoresistance (MRab = (ρab(H)−ρab(0))/ρab(0) × 100%) at different temperatures were also studied. The single crystals with x = 0.44 and 0.55 show a strong anisotropic MRab. For the x = 0.55 sample, MRab reaches 80% with a magnetic field of 14 T applied along the c-axis, while MRab is less than 5% for the magnetic field applied within the ab-plane. These results can be well understood in the light of the anisotropic Fermi surface in the multiband system.
Electron diffraction study of the structures of NbS2 and order—disorder in Cu‐intercalated NbS2
Structures of NbS2 and Nb1.05S2 single crystals, as well as structures of CuxNbS2 (x = 0.07, 0.25, 0.33, 0.50, and 0.67) single crystals as a function of temperature were examined by electron diffraction. A trigonal symmetry was observed in diffraction patterns of Nb1.05S2 and attributed to the failure of Friedel's law, as a combination of NbS2 polytypes can be non-centrosymmetric. Over certain temperature ranges diffuse intensity rings, surrounding the main diffraction spots of Nb1.05S2 and CuxNbS2, were observed and attributed to the short-range-order of non-stoichiometric Nb or Cu. At lower temperatures Cu ions formed one or two superstructures due to electrostatis interactions between them. Models for these structures are described and the calculated intensities are in good agreement with the experimental observations. 
 
 
 
Strukturen von NbS2- und Nb1,05S2-Einkristallen, sowie die Strukturanderungen in CuxNbS2 (x = 0,07; 0,25; 0,33; 0,50 und 0,67)-Einkristallen als Funktion der Temperatur wurden mit Elektronenbeugung untersucht. Im Beugungsdiagramm von Nb1,05S2 wurde trigonale Symmetrie gefunden und der Verletzung des Friedelschen Gesetzes zugeschrieben, da eine Kombination von NbS2-Polytypen nicht-zentrosymmetrisch sein kann. Diffuse Intensitatsringe, die in bestimmten Temperaturbereichen die meisten Beugungsflecken von Nb1,05S2 und CuxNbS2 umgeben, wurden der Nahordnung des nicht-stochiometrischen Nb oder Cu zugeschrieben. Bei tieferen Temperaturen bilden die Cu-Ionen eine oder zwei Superstrukturen, die auf Basis der elektrostatischen Wechselwirkung erklart werden konnen. Modelle fur diese Strukturen werden angegeben und die berechneten Intensitaten sind in guter ubereinstimmung mit den experimentellen Beobachtungen.
On the magnetic behavior of new 2HNbS2-type derivatives
Abstract The magnetic behavior of compounds of the type TxNbS2 with x = 1 3 and x = 1 4 was studied below room temperature. No magnetic order was found with T = Ti and V, whereas with Cr the phases with x = 1 3 become ferromagnetic.