Growth and Nanofabrication of All-Perovskite Superconducting/Ferromagnetic/Superconducting Junctions

Journal Article · Sun Sep 15 00:00:00 EDT 2019 · Journal of Superconductivity and Novel Magnetism

DOI:https://doi.org/10.1007/S10948-019-5023-6· OSTI ID:22922900

Golod, T. ^[1]; Bernhard, C. ^[2]; Krasnov, V. M. ^[1]

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1. Stockholm University, Department of Physics (Sweden)
2. University of Fribourg, Physics Department and Fribourg Center for Nanomaterials (FriMat) (Switzerland)

We fabricate and study experimentally all-perovskite-oxide superconductor/ferromagnetic insulator/superconductor (S/FI/S) tunnel junctions made out of the high-temperature cuprate superconductor YBa{sub 2}Cu{sub 3}O{sub 7−y} (YBCO) and the colossal magnetoresistive manganite LaMnO{sub 3} (LMO) in the ferromagnetic insulator state. YBCO/LMO/YBCO heterostructures with different LMO thicknesses (5, 10, and 20 nm) are grown epitaxially via pulsed laser deposition. Nanoscale S/FI/S junctions with sizes down to 300 nm are made by three-dimensional nano-sculpturing with focused ion beam. Junctions with a thick (20 nm) LMO barrier exhibit a large negative magnetoresistance below T{sub Curie}∼160 K, typical for colossal magnetoresistive manganites, as well as a kink in the current-voltage characteristics at large bias (V∼1–2 Volts), attributed to Zener-type tunneling. However, they do not show a measurable Josephson current. On the contrary, junctions with the thinnest 5-nm LMO barrier exhibit a large supercurrent and no signs of magnetism. The latter may indicate the presence of pinholes due to thickness inhomogeneity and/or a ∼ 2 nm dead magnetic layer at the YBCO / LMO interface caused, e.g., by interdiffusion or strain. The junction with an intermediate 10-nm LMO barrier exhibited a desired S/FI/S junction behavior with significant negative magnetoresistance and signatures of a small Josephson current.

• OSTI ID: 22922900
• Journal Information: Journal of Superconductivity and Novel Magnetism, Vol. 32, Issue 9; Conference: ICSM2018: 6. International Conference on Superconductivity and Magnetism, Antalya (Turkey), 29 Apr - 4 May 2018; Other Information: Copyright (c) 2019 Springer Science+Business Media, LLC, part of Springer Nature; Article Copyright (c) 2019 The Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 1557-1939
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
77 NANOSCIENCE AND NANOTECHNOLOGY
BARIUM OXIDES
COPPER OXIDES
CUPRATES
ENERGY BEAM DEPOSITION
EPITAXY
HIGH-TC SUPERCONDUCTORS
ION BEAMS
JOSEPHSON JUNCTIONS
LANTHANUM COMPOUNDS
LASER RADIATION
LAYERS
MAGNETISM
MAGNETORESISTANCE
MANGANATES
NANOSTRUCTURES
PEROVSKITES
PULSED IRRADIATION
TUNNEL EFFECT
YTTRIUM OXIDES