Point contact tunnelling apparatus with temperature and magnetic field control

• Published in: Cryogenics (Guildford) 1998-09, Vol.38 (9), p.911-915
• Main Authors: Ozyuzer, L., Zasadzinski, J.F., Gray, K.E.
• Format: Article
• Language: English
• Subjects: Barium compounds; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cryogenics, refrigerators; low-temperature techniques; cryostat; Cryostats; Electron tunneling; Energy gap; Exact sciences and technology; High temperature superconductors; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Magnetic field effects; Multilayers, superlattices , heterostructures; Physics; Point contacts; Spectroscopic analysis; Superconducting films and low-dimensional structures; Superconductivity; superconductors; Thermal effects; Thermal instruments, apparatus and techniques; tunnelling spectroscopy
• ISSN: 0011-2275; 1879-2235
• DOI: 10.1016/S0011-2275(98)00060-5

The design and testing of a new device for point contact tunnelling measurements in superconductors are described. The insert is designed for use with a continuous flow cryostat which allows for a large range of sample temperatures from 1.5 K to room temperature. The use of nonmagnetic parts allows tunnelling measurements to be performed in high magnetic fields. Testing was carried out on a conventional superconductor, Nb, in fields up to 6 T using Nb and Au tips to obtain superconductor–insulator–superconductor and superconductor–insulator–normal metal junctions. In addition, a moderate- T c oxide superconductor, Ba 1−xK xBiO 3, was used to obtain temperature and magnetic field dependencies of the energy gap.