Low Temperature Physics: 47, 96 (2021); https://doi.org/10.1063/10.0003167
Fizika Nizkikh Temperatur: Volume 47, Number 2 (February 2021), p. 110-114 ( to contents , go back )
Critical fields and features of electromagnetic transport of Bi2Se3 whiskers at low temperatures
Anatoly Druzhinin, Igor Ostrovskii, Yuriy Khoverko, Natalia Liakh-Kaguy, and Valeria Mazur
Department of semiconductor electronics Lviv Polytechnic National University, Lviv, Ukraine
Received September 17, 2020, published online December 25, 2020
The temperature dependences of resistance of n-type conductivity Bi2Se3 whiskers with doping concentration (1–2)⋅1019 cm–3 were studied in the temperature range 1.6–300 K. The sharp drop of the resistance was detected that is a result of a partial transition to the superconductive state at the critical temperature Тс = 5.3 K and probably due to the inclusion of β-PdBi2 phase in the studied samples. The transverse magnetoresistance of Bi2Se3 whiskers with various concentration of Pd doping impurity corresponding to the metal side of metal–insulator transition was studied in a magnetic field of 0–10 T. Superconductivity suppression effect by the magnetic field was found that permits to create the basic parameters such as the upper critical field Bc2 = 1.5 T, the coherence length of the superconductor ξ (0) = 15 nm and the superconducting gap Δ ≈ 0.8 meV. Studies of the n-type conductivity Bi2Se3 whiskers allow to create on their basis magnetic field sensors with a sensitivity of about 3.5 % / T, capable in the temperature range of 4.2–77 K. The investigated crystals can also be used in the magnetic switch-control sensors magnetic switches due to the transition to the superconducting state at the critical temperature Тс, depending on a magnetic field induction.
Key words: Bi2Se3 whiskers, transverse and longitudinal magnetoresistance, superconductivity, magnetic switch-control sensor.