Superconducting and spin-dependent tunneling using native oxide barriers on CoFe thin films

C. L. Platt; A. S. Katz; E. P. Price; R. C. Dynes; A. E. Berkowitz

doi:10.1103/PhysRevB.61.68

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Superconducting and spin-dependent tunneling using native oxide barriers on CoFe thin films

C. L. Platt, A. S. Katz, E. P. Price, R. C. Dynes, A. E. Berkowitz

DOI 10.1103/PhysRevB.61.68 · Physical Review B

T1

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Abstract

Superconducting tunneling and magnetoresistance were exhibited in junctions with native oxide barriers grown by exposing thin films of Co50Fe50 to ambient atmosphere. When Pb was used as a counterelectrode, I−V curves at 4.2 K reflected the presence of the superconducting energy gap of Pb. Conductance measurements at 1.5 K revealed clear longitudinal and transverse phonon structure from the superconducting Pb as evidence of single-step, elastic tunneling. Junctions with Co counterelectrodes showed a maximum tunneling magnetoresistance of 2.5% at room temperature and 6% at 77 K. These are the largest values reported to date in spin-dependent tunnel junctions using a native oxide barrier. Junction performance depended strongly on the deposition conditions for the top ferromagnetic layer.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Pb Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	7.2	Pressure unresolved	unknown