Superconducting FeSe_1−xTe_x Single Crystals Grown by Optical Zone-Melting Technique

Abstract

A new approach to grow FeSe 1-x Te x single crystals with optical zone-melting technique was successfully employed. Crystals with actual composition 0.4 ≤ x ≤ 1.0 all show high crystallinity with no phase separation. The ability to visually observe the locally heated melt, and ease of use and control of the image furnace make this method a promising and time-efficient way for obtaining highquality FeSe 1-x Te x crystals. Our results indicate that with adequate heat treatment, the non-uniform distribution of Se and Te atoms in crystal lattice can be effectively eliminated, while the transition width of superconductivity can be reduced to about 2 K, which suggest the crystals are homogeneous in nature.

Intrinsic pinning by naturally occurring correlated defects in FeSe1−xTexsuperconductors

“…c lattice parameter of the tetragonal and hexagonal phases as a function of the content of Te. Square symbols show data from the literature [7,8,9,10,11,12,13,14,15,16].…”

Consequences of Broken Translational Symmetry inFeSexTe1−x

“…Single crystals of Fe 1.03 Se 0.26 Te 0.74 with T c ¼ 13 K were grown by optical zone melting [18]. Samples were cleaved in situ to expose a clean (001) surface.…”

Low-temperature synthesis of FeTe0.5Se0.5polycrystals with a high transport critical current density

“…Recently, by introducing alkali metal K (Cs, Rb) into this 11 system to form a ternary compound, T c is increased up to 30 K [11][12][13]. In addition to the very simple crystal structure, the very high values of upper critical field make this system a potential candidate for practical applications [14][15][16][17][18]. Also critical current density, J c , in a high-quality single crystal is reported to be over 1×10 5 A/cm 2 [18][19][20].…”

“…The value of H c2 at T = 0 K estimated using the Werthamer-Helfand-Hohenberg formula [32], H c2 (0)=−0.69T c |dH c2 /dT| T=Tc , is 585 kOe. This value is comparable to the single crystals [14][15][16][17][18]. In order to extract the superconducting parameters, we have used the Ginzburg-Landau (GL) formula for the coherence length (ξ), ξ= (Φ 0 /2πH c2 ) 1/2 , where Φ 0 = 2.07×10 −7 G cm 2 , the coherence length ξ at the zero temperature is calculated as 2.38 nm.…”