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.
Influence of the low Mn intercalation on magnetic and electronic properties of 2H-TaS2 single crystals
Abstract The low-Mn-intercalated compounds 2H-Mn x TaS 2 ( x ≤0.1) single crystals were successfully grown via the iodine chemical vapor transport technique; the electrical and magnetic properties have been investigated systematically. No signs of charge density wave and superconductivity transitions appear down to 2 K even when x =0.02, while a small resistivity upturn has been observed in the low-temperature region for Mn x TaS 2 samples. A substantial magnetocrystalline anisotropy is observed and the Mn magnetic moments lie mainly parallel to the ab-plane. The glass behavior was observed in the low-temperature region firstly from the ac susceptibility measurement, the freezing of the glass may contribute to the upturn of the resistivity.
Photoreflectance characterization of vanadium-doped GaAs layers grown by metalorganic vapor phase epitaxy
Abstract We characterized the vanadium-doped (GaAs:V) layers grown on GaAs substrate by metalorganic vapor phase epitaxy. The conductivity of the samples is checked by the Hall effect measurements, and it is n type with electrons concentration ranging from 2×10 13 to 2×10 17  cm −3 . We used the photoreflectance technique (PR) to study the effect of vanadium doping on the optical properties of GaAs. Our experimental results show that the built-in electric field F and the broadening parameter Γ 0 increase with V-doping concentration. Furthermore, the temperature dependence of the built-in electric field and the broadening parameter of GaAs:V samples have been investigated by PR. It has been observed that these parameters increase with increasing temperature. The decrease of the built-in electric field with decreasing temperature is due to the photovoltage effect.We characterized the vanadium-doped GaAs (GaAs:V) layers grown on GaAs substrate by metalorganic vapor phase epitaxy.