Improvements of high-field pinning properties of polycrystalline Fe(Se,Te) material by heat treatments

• Published in: Journal of materials science Vol. 54; no. 6; pp. 5092 - 5100
• Main Authors: Fiamozzi Zignani, C., De Marzi, G., Corato, V., Mancini, A., Vannozzi, A., Rufoloni, A., Leo, A., Guarino, A., Galluzzi, A., Nigro, A., Polichetti, M., della Corte, A., Pace, S., Grimaldi, G.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-03-2019; Springer; Springer Nature B.V
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Classical Mechanics; Configuration management; Cooling rate; Critical current density; Crystallography and Scattering Methods; Heat treating; Heat treatment; High temperature; High temperature superconductors; Iron; Magnetic fields; Magnetism; Magnetization; Magnetization curves; Materials Science; Metals; Performance enhancement; Phase diagrams; Polycrystals; Polymer Sciences; Solid Mechanics; Temperature dependence; YBCO superconductors
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-018-03218-5

We present the fabrication of FeSe
0.5
Te
0.5
polycrystalline samples by self-flux method, showing the presence of the peak-effect in the vortex lattice configuration. To improve the performances at high magnetic fields for this iron-based superconductor of the 11-family, the two-step solid-state reaction process has been successfully modified by increasing the temperature of the heat treatment and by slowing down the cooling rate. The magnetic field-temperature phase diagram has been investigated by magneto-resistance, magnetization, and heat capacity measurements in applied magnetic fields up to 18 T. The magnetization curves exhibit an enhancement of the peak-effect whose position shifts by varying the temperature, following a similar dependence than that previously reported in high-temperature superconducting materials such as YBa
2
Cu
3
O
7-δ
. The presence of the peak-effect can be correlated to the sample manufacture, since by tuning a proper heat treatment it becomes observable ever more in the magnetic field-temperature phase diagram. This fabrication route paves the way to a systematic increase in the critical current density thus becoming relevant for applications.