Improvement in the Magnetic Properties of Ni–Fe Thin Films on Thick Nb Electrodes Using Oxidation and Low-Energy Ar Ion Milling

Singh, Rakesh Kumar; Rizzo, Nicholas D.; Bertram, M.; Zheng, Kaiwen; Newman, Nathan

doi:10.1109/lmag.2017.2776079

Cited by 2 publications

(2 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…36,37 We have found that magnetic films grown on the multilayer have better magnetic properties than similar films grown on thick Nb. Other groups have reached similar conclusions using other methods of planarization, such as oxidation and ion milling 38 or deposition of an Al/Cu seed bilayer between the Nb and the ferromagnetic layer. 39 This issue is an area of ongoing research.…”

Section: Optimization Of Spin-valve Junctions For Cryogenic Memorymentioning

confidence: 60%

Ferromagnetic Josephson junctions for cryogenic memory

Birge,

Madden,

Naaman

2018

Preprint

View full text Add to dashboard Cite

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.

show abstract

Section: Optimization Of Spin-valve Junctions For Cryogenic Memorymentioning

confidence: 60%

Ferromagnetic Josephson junctions for cryogenic memory

Birge,

Madden,

Naaman

2018

Preprint

View full text Add to dashboard Cite

show abstract

“…There have been numerous reports concerning the supercurrent passing through ferromagnetic Josephson junctions, including the discovery of spin triplet pair correlations in these systems [19][20][21][22][23][24][25][26]. In order to improve the properties of the thin ferromagnetic layers in the Josephson junctions, it is important that the surface roughness of the Nb electrode be as small as possible [27]. It has long been known that introducing a thin Al layer between Nb films improves the surface roughness compared to Nb films of equivalent thickness; this is understood to be due to the Al forming amorphously and thus preventing columnar growth of Nb [28][29][30].…”

Section: Introductionmentioning

confidence: 99%

Distortions to the penetration depth and coherence length of superconductor/normal-metal superlattices

Quarterman

Satchell

Kirby

et al. 2020

Phys. Rev. Materials

View full text Add to dashboard Cite

Superconducting (S) thin film superlattices composed of Nb and a normal metal spacer (N) have been extensively utilized in Josephson junctions given their favorable surface roughness compared to Nb films of comparable thickness. In this work, we characterize the London penetration depth and Ginzburg-Landau coherence lengths of S /N superlattices using polarized neutron reflectometry and electrical transport. Despite the normal metal spacer layers being only approximately 8% of the total superlattice thickness, we surprisingly find that the introduction of these thin N spacers between S layers leads to a dramatic increase in the measured London penetration depth compared to that of a single Nb film of comparable thickness. Using the measured values for the effective inand out-of-plane coherence lengths, we quantify the induced anisotropy of the superlattice samples and compare to a single Nb film sample. From these results, we find that that the superlattices behave similarly to layered 2D superconductors.

show abstract

Improvement in the Magnetic Properties of Ni–Fe Thin Films on Thick Nb Electrodes Using Oxidation and Low-Energy Ar Ion Milling

Cited by 2 publications

References 13 publications

Ferromagnetic Josephson junctions for cryogenic memory

Ferromagnetic Josephson junctions for cryogenic memory

Distortions to the penetration depth and coherence length of superconductor/normal-metal superlattices

Contact Info

Product

Resources

About