The physical properties of Hastelloy® C-276TM and Hastelloy® C-276TM with Al2O3/Y2O3/MgO/LaMnO3 buffer layers down to cryogenic temperatures for applications in superconducting magnets

•Superconducting tapes on Hastelloy provide high critical current density, low AC losses, high magnetic field performance. For many years, the Ni–Mo–Cr superalloy Hastelloy® C-276™ has been employed as a substrate material for depositing superconducting REBa2Cu3O7-x (RE - rare earth element) and MgB2 layers with various intermediate buffer layers. The resulting superconducting tapes are widely used in various industrial applications. However, the presence of various intermediate buffer layers between the substrate and the superconducting layer can influence the magnetic and thermal properties. At present, there is a dearth of significant data in literature concerning the impact of buffer layers. In this study, we provide data on the physical properties of a commercial Hastelloy® C-276™ tape with deposited Al2O3/Y2O3/MgO/LaMnO3 buffer layers, along with an electro-polished Hastelloy® C-276™ substrate. Physical properties such as magnetic susceptibility (dc) and specific heat, Cp, were measured from 5 to 300 K and the chemical composition was investigated. In low magnetic fields and relevant temperature range (5–200 K), the magnetization of a Hastelloy substrate demonstrates the Curie law, while Hastelloy with deposited buffer layers demonstrates Curie-Weiss law. At the magnetic field of 9 T and temperature 5 K, the resultant relative specific magnetization, compared to electro-polished Hastelloy, was lower by 16%. For heat capacity, Debye T3 law provides a good approximation from 22 to 48 K but the impact of buffer layers at 100 K was higher by 9.5%, compared to electro-polished Hastelloy, and decreases gradually with decreasing the temperature.