Phase diagrams on composition-spread Fe Te1−Se films

Reassembled phase diagram for Fe y Se x Te1−x superconducting films grown by pulsed laser deposition

“…Combined with the results that the planar defects dominant only in the Fe 1.28 Se 0.32 Te 0.68 film, we can speculate that the planar defects are not conducive to the robustness of the H c2 to the temperature. Figure 6 shows the T c, onset phase diagram for ternary Fe y Se x Te 1−x superconducting films deposited on the CaF 2 substrate, based on the data obtained from the current work, the unpublished work and the previous literatures [11,37,[47][48][49]. Obviously, both the Fe and Se content can greatly affect the T c, onset , and the superconductivity of the Fe y Se x Te 1−x films can be observed over a wide range of Fe content (0.67 ⩽ y ⩽ [11,37,[47][48][49].…”

“…Figure 6 shows the T c, onset phase diagram for ternary Fe y Se x Te 1−x superconducting films deposited on the CaF 2 substrate, based on the data obtained from the current work, the unpublished work and the previous literatures [11,37,[47][48][49]. Obviously, both the Fe and Se content can greatly affect the T c, onset , and the superconductivity of the Fe y Se x Te 1−x films can be observed over a wide range of Fe content (0.67 ⩽ y ⩽ [11,37,[47][48][49]. The red region means that the FeSeTe film with the corresponding composition exhibits a higher Tc, onset, while the blue region means that the FeSeTe film with the corresponding composition exhibits a lower Tc, onset.…”

“…The T c of FeSe bulk superconductor is around 8 K, and can be rapidly raised to 15 K by doping 50% Te element [7]. The superconductivity of FeSeTe is extremely sensitive to its compositional variation and exhibits rich phase diagrams [8][9][10][11]. It can be found that the Se content can significantly affect the T c , structural transition and magnetism of FeSeTe superconductors.…”

“…In previous studies, most constructed phase diagrams of Fe y Se x Te 1−x superconductor were based on the change of Se content while a thorough phase diagram of Fe content is still lacking [8][9][10][11]. This is mainly because that, in bulk materials, extra Fe is needed to stabilize the single-phase tetragonal FeSeTe, while Fe deficiency leads to phase separation [12][13][14][15].…”

“…Although crystalline lattice behaving instable for bulk materials, tetragonal phase can be stabilized utilizing the compressive stress from the substrate for FeSeTe films with Fe deficiency. It has been reported that FeSeTe superconductor still exhibits high T c at Fe content of 0.8 or less [11,14,24]. However, systematic study of the Fe dependence on superconductivity is still lacking.…”