Magnetic anisotropy of thin sputtered MgB2 films on MgO substrates in high magnetic fields

Abstract

We investigated the magnetic anisotropy ratio of thin sputtered polycrystalline MgB2 films on MgO substrates. Using high magnetic field measurements, we estimated an anisotropy ratio of 1.35 for T=0 K with an upper critical field of 31.74 T in the parallel case and 23.5 T in the perpendicular case. Direct measurements of a magnetic-field sweep at 4.2 K show a linear behavior, confirmed by a linear fit for magnetic fields perpendicular to the film plane. Furthermore, we observed a change of up to 12% of the anisotropy ratio in dependence of the film thickness.

4 pages, 4figures

References in corpus (10)

• Very high upper critical fields in MgB2 produced by selective tuning of impurity scattering
• Type-1.5 Superconductors
• Thermodynamics of the Mg-B system: Implications for the deposition of MgB2 thin films
• Anisotropy of the Upper Critical Field and Critical Current in Single Crystal MgB${}_2$
• Electronic anisotropy, magnetic field-temperature phase diagram and their dependence on resistivity in c-axis oriented MgB2 thin films
• Fermi surface topology and the upper critical field in two-band superconductors - application to MgB2
• Anisotropy of superconducting MgB2 as seen in electron spin resonance and magnetization data
• Anisotropic Superconductivity in Epitaxial MgB2 Films
• Temperature and bias voltage dependence of Co/Pd multilayer-based magnetic tunnel junctions with perpendicular magnetic anisotropy
• Spin polarized tunneling in MgO-based tunnel junctions with superconducting electrodes