Fe–Te–Se epitaxial thin films with enhanced superconducting properties

Abstract

Epitaxial Fe–Te–Se thin films were deposited by pulsed laser deposition at 250–600 °C on SrTiO3 (100), MgO (100), LaAlO3 (100) and CaF2 (100) single crystal substrates. The best superconducting film was grown on CaF2: K and K with Tdep = 300 °C and 3 Hz. Critical current density Jc (T = 4.2 K) was 0.41 × 106 A cm−2 at 0 T and 0.23 × 106 A cm−2 at 9 T. The angular dependence of Jc shows a broad c-axis correlated peak when B ≥ 3 T.

Influence of substrate type on transport properties of superconducting FeSe0.5Te0.5thin films

“…Furthermore, films on SrTiO 3 show a peak in the angular dependence of J c for H || c [11][12][13]. Similar c-axis peaks in J c (θ) have been observed for films deposited on CaF 2 substrate [14]. However, no additional peaks have been observed in FeSe 0.5 Te 0.5 films on LAO [11] and Fe-buffered MgO substrates [15][16].…”

Superconducting properties of iron chalcogenide thin films

“…They state that the key to high-quality 11 thin films is the absence of interfacial reactions between the FeTeSe film and the substrate (figure 7). Mele et al [15] and Bellingeri et al [16,[39][40][41] confirmed that smooth, cube-on-cube epitaxial FeTe 0.5 Se 0.5 films can be obtained on several substrates: MgO, LAO, STO, yttria-stabilized zirconia (YSZ), MgO, CaF 2 and LiF. Iida et al [14] reported for the first • to the MgO substrate, whereas the FeTeSe film showed the cube-on-cube epitaxial relation (figure 8).…”

“…Mele et al [15] systematically analyzed the dependence of T c of FeTeSe/CaF 2 films on the experimental parameters, exploring a wide range of deposition temperatures (from 250 to 450…”

“…Mele et al [15] reported that FeTe 0.5 Se 0.5 films deposited on LAO had a compressed c-axis (c = 5.9293 versus 5.9784 Å in the bulk), but their T c was lower than in the corresponding bulk material (T 0 c = 7.47 versus 13.5 K in the bulk). They also Imai et al [36] showed that a thin FeTe 0.5 Se 0.5 film (50 nm) deposited on CaF 2 at 300…”

“…The quality of 11 thin films was greatly enhanced recently, Table 1. Summary of deposition parameters of iron chalcogenide epitaxial films prepared by PLD on various single crystal substrates, including SrTiO Torr O 2 [26] and high current densities, J c , in magnetic field have been reported [12][13][14][15][16]. Excellent reviews on bulk iron chalcogenides have been published as dedicated papers [17] or as chapters in extended overviews of all iron-based superconductors [18][19][20][21][22][23].…”