Ferromagnetic Josephson junctions for cryogenic memory

Abstract

Josephson junctions containing ferromagnetic materials have attracted intense interest both because of their unusual physical properties and because they have potential application for cryogenic memory. There are two ways to store information in such a junction: either in the amplitude of the critical current or in the ground-state phase difference across the junction; the latter is the topic of this paper. We have recently demonstrated two different ways to achieve phase control in such junctions: the first uses junctions containing two magnetic layers in a "pseudo spin valve" configuration, while the second uses junctions containing three magnetic layers with non-collinear magnetizations. The demonstration devices, however, have not yet been optimized for use in a large-scale cryogenic memory array. In this paper we outline some of the issues that must be considered to perform such an optimization, and we provide a speculative "phase-diagram" for the nickel-permalloy spin-valve system showing which combinations of ferromagnetic layer thicknesses should produce useful devices.

arXiv commentsubmitted to SPIE Conference Proceedings

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Cited by in corpus (8)

• Phase Controllable Josephson Junctions for Cryogenic Memory
• Spin-valve Josephson junctions with perpendicular magnetic anisotropy for cryogenic memory
• Locking of magnetization and Josephson oscillations at ferromagnetic resonance in ${\phi }_0$ junction under external radiation
• Spin-Singlet and Spin-Triplet Josephson Junctions for Cryogenic Memory
• Vertical transport and tunnelling in rare-earth nitride heterostructures
• Distortions to the penetration depth and coherence length of superconductor/normal-metal superlattices
• Superconducting Pulse Conserving Logic and Josephson-SRAM
• Comparison of NiFeCr and NiFe in ferromagnetic Josephson junctions