A novel iron-based superconductor synthesized by the ion exchange technique

• Published in: New journal of physics Vol. 24; no. 4; pp. 43035 - 43041
• Main Authors: Hu, G B, Shi, M Z, Wang, W X, Zhu, C S, Luo, X G, Chen, X H
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.04.2022
• Subjects: Chemical synthesis; Ethylene glycol; FeSe-based superconductor; High temperature; Ion exchange; Iron; Low temperature; Magnetic permeability; Methods; nearly vacancy-free precursor; Photoelectrons; Physics; Precursors; Single crystals; Superconductivity; Superconductors; Transition temperature; Vacancies
• ISSN: 1367-2630; 1367-2630
• DOI: 10.1088/1367-2630/ac6319

Abstract The superconductivity of the FeSe-based superconductor is extremely sensitive to Fe vacancies in the FeSe plane. In order to reduce the formation of Fe vacancies in the FeSe plane, various low-temperature methods are developed. However, it is still complex and time consuming to control the Fe vacancies concentration. Here, a hybrid iron-based superconductor, Li 0.21 Se 0.05 (EG) 0.26 FeSe (EG: ethylene glycol, C 2 H 6 O 2 ), is synthesized by a solvothermal ion-exchange technique using a nearly vacancy-free precursor of (TBA) 0.3 FeSe as the matrix. Bulk superconductivity with transition temperature ( T c ) of 30 K is confirmed by the characterization with the magnetic susceptibility and resistivity measurements. Compared with the pristine FeSe single crystal, x-ray photoelectron spectroscopy results show a decrease of the Fe valence, indicating that electron doping to FeSe plane accounts for the increase of the T c . Our result suggests that (TBA) 0.3 FeSe, a nearly vacancy-free precursor with a large distance between the adjacent FeSe planes, is a good template candidate for the synthesis of other hybrid iron-based superconductors using the ion exchange technique.