Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userCrystal Growth and Magneto-transport of Bi2Se3 Single crystals
102
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
In this letter, we report growth and characterization of bulk Bi2Se3 single crystals. The studied Bi2Se3 crystals are grown by self flux method through solid state reaction from high temperature (950C) melt of constituent elements and slow cooling (2C/hour). The resultant crystals are shiny and grown in [00l] direction, as evidenced from surface XRD. Detailed Reitveld analysis of PXRD (powder x-ray diffraction) of the crystals showed that these are crystallized in rhombohedral crystal structure with space group of R3m (D5) and the lattice parameters are a = 4.14(2)A, b = 4.14 (2) A and c = 28.7010(7) A. Temperature versus resistivity (R-T) plots revealed metallic conduction down to 2K, with typical room temperature resistivity (R300K) of around 0.53 mohm-cm and residual resistivity of 0.12 mohm-cm. Resistivity under magnetic field ] measurements exhibited large +Ve magneto resistance right from 2K to 200K. Isothermal magneto resistance [RH] measurements at 2K, 100K and 200K exhibited magneto resistance (MR) of up to 240, 130 and 60 percent respectively at 14 Tesla. Further the MR plots are non saturating and linear with field at all temperature. At 2K the MR plots showed clear quantum oscillations at above say 10 Tesla applied field. Also the Kohler plots i.e., were seen consolidating on one plot. Interestingly, the studied Bi2Se3 single crystal exhibited the Shubnikov-de Haas oscillations (SdH) at 2K under different applied magnetic fields ranging from 4Tesla to 14 Tesla
rate research
Read More
A detailed investigation on the structural and magneto-transport properties of iron intercalated Bi2Se3 single crystals have been presented. The x-ray diffraction and Raman studies confirm the intercalation of Fe in the van der Waals gaps between the layers. The electrical resistivity of the compounds decreases upon intercalation, and Hall resistivity shows the enhancement of the charge carriers upon intercalation. The magnetoresistance shows the non-saturating linear behavior at higher magnetic field and low temperature. Intercalation of Fe increases the onset of the linear magnetoresistance behavior, indicating the reduction in quantum effects. The Kohler scaling employed on the magnetoresistance data indicates single scattering process for all these compounds in the measured temperature range of 3- 300 K.
Single crystal of YCoGa5 has been grown via Ga self-flux. In this paper, we report the single crystal growth, crystallographic parameters, resistivity, heat capacity, and band structure results of YCoGa5. YCoGa5 accommodates the HoCoGa5 type structure (space group P4/mmm (No. 123), Z = 1, a = 4.2131(6) A, c = 6.7929(13) A, which is isostructural to the extensively studied heavy fermion superconductor system CeMIn5 (M = Co, Rh, Ir) and the unconventional superconductor PuCoGa5 with Tc = 18.5 K. No superconductivity is observed down to 1.75 K. Band structure calculation results show that its band at the Fermi level is mainly composed of Co-3d and Ga-4p electrons states, which explains its similarity of physical properties to YbCoGa5 and LuCoGa5.
Superconductivity was discovered in a Ni0:05TaS2 single crystal. A Ni0:05TaS2 single crystal was successfully grown via the NaCl/KCl flux method. The obtained lattice constant c of Ni0:05TaS2 is 1.1999 nm, which is significantly smaller than that of 2H-TaS2 (1.208 nm). Electrical resistivity and magnetization measurements reveal that the superconductivity transition temperature of Ni0:05TaS2 is enhanced from 0.8 K (2H-TaS2) to 3.9 K. The charge-density-wave transition of the matrix compound 2H-TaS2 is suppressed in Ni0:05TaS2. The success of Ni0:05TaS2 single crystal growth via a NaCl/KCl flux demonstrates that NaCl/KCl flux method will be a feasible method for single crystal growth of the layered transition metal dichalcogenides.
We report flux free growth of superconducting FeSe single crystals by an easy and versatile high temperature melt and slow cooling method for first time. The room temperature XRD on the surface of the piece of such obtained crystals showed single 101 plane of Beta-FeSe tetragonal phase. The bulk powder XRD, being obtained by crushing the part of crystal chunk showed majority tetragonal and minority FeSe hexagonal crystalline phases. Detailed HRTEM images along with SAED (selected area electron diffraction) showed the abundance of both majority and minority FeSe phases. Both transport (RT) and magnetization (MT) exhibited superconductivity at below around 10K. Interestingly, the magnetization signal of these crystals is dominated by the magnetism of minority magnetic phase, and hence the isothermal magnetization (MH) at 4K was seen to be ferromagnetic (FM) like. Transport (R-T) measurements under magnetic field showed superconductivity onset at below 12K, and R = 0 (Tc) at 9K. Superconducting transition temperature (Tc) decreases with applied field to around 6K at 7Tesla, with dTc/dH of 0.4K/Tesla, giving rise to an Hc2 value of around 50 Tesla, 30 Tesla and 20 Tesla for Rn = 90, 50 and 10 percent respectively. FeSe single crystal activation energy is calculated from Thermally Activated Flux Flow (TAFF) model which is found to decreases with field.
Here we report the growth of sub-millimeter MgB2 single crystals of various shapes under high pressure in Mg-B-N system. Structure refinement using a single-crystal X-ray diffraction analysis gives lattice parameters a=3.0851(5) A and c=3.5201(5) A with small reliability factors (Rw =0.025, R=0.018), which enables us to analyze the Fourier and Fourier difference maps. The maps clearly show the B sp2 orbitals and covalency of the B-B bonds. The sharp superconducting transitions at Tc =38.1-38.3K were obtained in both magnetization (DTc =0.6K) and resistivity (DTc <0.3K) measurements. Resistivity measurements with magnetic fields applied parallel and perpendicular to the Mg and B sheets reveal the anisotropic nature of this compound, with upper critical field anisotropy ratio of about 2.7.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
