Synthesis and characterization of Ti-doped Bi4O4S3 superconductor

• Published in: Applied physics. A, Materials science & processing Vol. 125; no. 12; pp. 1 - 8
• Main Authors: Monteiro, João Frederico Haas Leandro, Barcote, Marcos Vinicius Woiski, Jurelo, Alcione Roberto, Siqueira, Ezequiel Costa
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.12.2019; Springer Nature B.V
• Subjects: Applied physics; Characterization and Evaluation of Materials; Condensed Matter Physics; Diamagnetism; Doping; Ferromagnetism; Machines; Magnetic moments; Manufacturing; Materials science; Nanotechnology; Optical and Electronic Materials; Physics; Physics and Astronomy; Processes; Raman spectroscopy; Room temperature; Spectrum analysis; Substitution reactions; Superconductivity; Surfaces and Interfaces; Thin Films; Titanium; Transition metals
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-019-3119-2

The substitution effects of 3 d 2 transition metal Ti on the Bi 4 O 4 S 3 superconductor structure were studied. The presence of Ti in Bi 2 O 2 layer spacer or superconducting BiS 2 layers was investigated. For this study, the polycrystalline Bi 4 O 4 S 3 superconductor was prepared following a two-step solid-state reaction. Grains consisted of lamellae, ~ 5–10 μm in the planar orientation and 100–500 nm thick, presenting a tetragonal crystalline structure, with space group I4/mmm. For the first time, Raman spectroscopy revealed three modes at room temperature, with no significant changes in the spectra with Ti doping. The superconductivity was observed by the Meissner effect from ZFC and FC magnetization measurements. For both samples, the critical temperature was around 3.5 K, showing that Ti doping did not change the T C value, probably due to fact that Ti is in the Bi 2 O 2 layer spacer. Also, the doped sample presented a strong positive magnetic moment, probably due to the presence of ferromagnetic order.