1
|
Vettoliere A, Satariano R, Ferraiuolo R, Di Palma L, Ahmad HG, Ausanio G, Pepe GP, Tafuri F, Massarotti D, Montemurro D, Granata C, Parlato L. High-Quality Ferromagnetic Josephson Junctions Based on Aluminum Electrodes. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:nano12234155. [PMID: 36500778 PMCID: PMC9736349 DOI: 10.3390/nano12234155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/17/2022] [Accepted: 11/21/2022] [Indexed: 06/12/2023]
Abstract
Aluminum Josephson junctions are the building blocks for the realization of superconducting quantum bits. Attention has been also paid to hybrid ferromagnetic Josephson junctions, which allow switching between different magnetic states, making them interesting for applications such as cryogenic memories, single-photon detectors, and spintronics. In this paper, we report on the fabrication and characterization of high-quality ferromagnetic Josephson junctions based on aluminum technology. We employed an innovative fabrication process inspired by niobium-based technology, allowing us to obtain very high-quality hybrid aluminum Josephson junctions; thus, supporting the use of ferromagnetic Josephson junctions in advanced quantum circuits. The fabrication process is described in detail and the main DC transport properties at low temperatures (current-voltage characteristic, critical current as a function of the temperature, and the external magnetic field) are reported. Here, we illustrate in detail the fabrication process, as well as the main DC transport properties at low temperatures (current-voltage characteristic, critical current as a function of the temperature, and the external magnetic field).
Collapse
Affiliation(s)
- Antonio Vettoliere
- Consiglio Nazionale delle Ricerche—ISASI, Via Campi Flegrei 34, I-80078 Pozzuoli, Italy
| | - Roberta Satariano
- Dipartimento di Fisica “Ettore Pancini”, Università degli Studi di Napoli Federico II, I-80125 Napoli, Italy
| | - Raffaella Ferraiuolo
- Dipartimento di Fisica “Ettore Pancini”, Università degli Studi di Napoli Federico II, I-80125 Napoli, Italy
- Consiglio Nazionale delle Ricerche—SPIN, c/o Complesso Monte Sant’Angelo, via Cinthia, I-80126 Napoli, Italy
| | - Luigi Di Palma
- Dipartimento di Fisica “Ettore Pancini”, Università degli Studi di Napoli Federico II, I-80125 Napoli, Italy
- Consiglio Nazionale delle Ricerche—SPIN, c/o Complesso Monte Sant’Angelo, via Cinthia, I-80126 Napoli, Italy
| | - Halima Giovanna Ahmad
- Consiglio Nazionale delle Ricerche—SPIN, c/o Complesso Monte Sant’Angelo, via Cinthia, I-80126 Napoli, Italy
- Dipartimento di Ingegneria Elettrica e delle Tecnologie dell’Informazione, Università degli Studi di Napoli Federico II, I-80125 Napoli, Italy
| | - Giovanni Ausanio
- Dipartimento di Fisica “Ettore Pancini”, Università degli Studi di Napoli Federico II, I-80125 Napoli, Italy
- Consiglio Nazionale delle Ricerche—SPIN, c/o Complesso Monte Sant’Angelo, via Cinthia, I-80126 Napoli, Italy
| | - Giovanni Piero Pepe
- Dipartimento di Fisica “Ettore Pancini”, Università degli Studi di Napoli Federico II, I-80125 Napoli, Italy
- Consiglio Nazionale delle Ricerche—SPIN, c/o Complesso Monte Sant’Angelo, via Cinthia, I-80126 Napoli, Italy
| | - Francesco Tafuri
- Dipartimento di Fisica “Ettore Pancini”, Università degli Studi di Napoli Federico II, I-80125 Napoli, Italy
- Consiglio Nazionale delle Ricerche—Istituto Nazionale di Ottica (CNR-INO), Largo Enrico Fermi 6, I-50125 Florence, Italy
| | - Davide Massarotti
- Consiglio Nazionale delle Ricerche—SPIN, c/o Complesso Monte Sant’Angelo, via Cinthia, I-80126 Napoli, Italy
- Dipartimento di Ingegneria Elettrica e delle Tecnologie dell’Informazione, Università degli Studi di Napoli Federico II, I-80125 Napoli, Italy
| | - Domenico Montemurro
- Dipartimento di Fisica “Ettore Pancini”, Università degli Studi di Napoli Federico II, I-80125 Napoli, Italy
- Consiglio Nazionale delle Ricerche—SPIN, c/o Complesso Monte Sant’Angelo, via Cinthia, I-80126 Napoli, Italy
| | - Carmine Granata
- Consiglio Nazionale delle Ricerche—ISASI, Via Campi Flegrei 34, I-80078 Pozzuoli, Italy
| | - Loredana Parlato
- Dipartimento di Fisica “Ettore Pancini”, Università degli Studi di Napoli Federico II, I-80125 Napoli, Italy
- Consiglio Nazionale delle Ricerche—SPIN, c/o Complesso Monte Sant’Angelo, via Cinthia, I-80126 Napoli, Italy
| |
Collapse
|
2
|
Kang K, Berger H, Watanabe K, Taniguchi T, Forró L, Shan J, Mak KF. van der Waals π Josephson Junctions. NANO LETTERS 2022; 22:5510-5515. [PMID: 35736540 DOI: 10.1021/acs.nanolett.2c01640] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Proximity-induced superconductivity in a ferromagnet can induce Cooper pairs with a finite center-of-mass momentum and stabilize Josephson junctions (JJs) with π phase difference in superconductor-ferromagnet-superconductor heterostructures. The emergence of two-dimensional layered superconducting and magnetic materials promises a new platform for realizing π JJs with atomically sharp interfaces. Here we demonstrate a thickness-driven 0-π transition in JJs made of NbSe2 (an Ising superconductor) and Cr2Ge2Te6 (a ferromagnetic semiconductor). By systematically increasing the Cr2Ge2Te6 weak link thickness, we observe a vanishing supercurrent at a critical thickness of ∼8 nm, followed by a re-entrant supercurrent. Near the critical thickness, we further observe unusual supercurrent interference patterns with vanishing critical current around zero in-plane magnetic field. They signify the formation of 0-π JJs (with both 0 and π regions), likely induced by the nanoscale magnetic domains in Cr2Ge2Te6.
Collapse
Affiliation(s)
- Kaifei Kang
- School of Applied and Engineering Physics, Cornell University, Ithaca 14850, New York, United States
| | - Helmuth Berger
- Institute of Condensed Matter Physics, Ecole Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland
| | - Kenji Watanabe
- National Institute for Materials Science, Tsukuba 305-0044, Japan
| | | | - László Forró
- Institute of Condensed Matter Physics, Ecole Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland
- Stavropoulos Center for Complex Quantum Matter, Department of Physics, University of Notre Dame, Notre Dame 46556, Indiana, United States
| | - Jie Shan
- School of Applied and Engineering Physics, Cornell University, Ithaca 14850, New York, United States
- Department of Physics, Cornell University, Ithaca 14850, New York, United States
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca 14850, New York, United States
| | - Kin Fai Mak
- School of Applied and Engineering Physics, Cornell University, Ithaca 14850, New York, United States
- Department of Physics, Cornell University, Ithaca 14850, New York, United States
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca 14850, New York, United States
| |
Collapse
|
3
|
Ai L, Zhang E, Yang J, Xie X, Yang Y, Jia Z, Zhang Y, Liu S, Li Z, Leng P, Cao X, Sun X, Zhang T, Kou X, Han Z, Xiu F, Dong S. Van der Waals ferromagnetic Josephson junctions. Nat Commun 2021; 12:6580. [PMID: 34772912 PMCID: PMC8589954 DOI: 10.1038/s41467-021-26946-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 10/25/2021] [Indexed: 11/17/2022] Open
Abstract
Superconductor-ferromagnet interfaces in two-dimensional heterostructures present a unique opportunity to study the interplay between superconductivity and ferromagnetism. The realization of such nanoscale heterostructures in van der Waals (vdW) crystals remains largely unexplored due to the challenge of making atomically-sharp interfaces from their layered structures. Here, we build a vdW ferromagnetic Josephson junction (JJ) by inserting a few-layer ferromagnetic insulator Cr2Ge2Te6 into two layers of superconductor NbSe2. The critical current and corresponding junction resistance exhibit a hysteretic and oscillatory behavior against in-plane magnetic fields, manifesting itself as a strong Josephson coupling state. Also, we observe a central minimum of critical current in some JJ devices as well as a nontrivial phase shift in SQUID structures, evidencing the coexistence of 0 and π phase in the junction region. Our study paves the way to exploring sensitive probes of weak magnetism and multifunctional building-blocks for phase-related superconducting circuits using vdW heterostructures.
Collapse
Affiliation(s)
- Linfeng Ai
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200433, Shanghai, China
- Shanghai Qi Zhi Institute, 41th Floor, AI Tower, No. 701 Yunjin Road, Xuhui District, 200232, Shanghai, China
| | - Enze Zhang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200433, Shanghai, China
| | - Jinshan Yang
- State Key Laboratory of High Performance Ceramics & Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 200050, Shanghai, China
| | - Xiaoyi Xie
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200433, Shanghai, China
- Shanghai Qi Zhi Institute, 41th Floor, AI Tower, No. 701 Yunjin Road, Xuhui District, 200232, Shanghai, China
| | - Yunkun Yang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200433, Shanghai, China
| | - Zehao Jia
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200433, Shanghai, China
- Shanghai Qi Zhi Institute, 41th Floor, AI Tower, No. 701 Yunjin Road, Xuhui District, 200232, Shanghai, China
| | - Yuda Zhang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200433, Shanghai, China
- Shanghai Qi Zhi Institute, 41th Floor, AI Tower, No. 701 Yunjin Road, Xuhui District, 200232, Shanghai, China
| | - Shanshan Liu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200433, Shanghai, China
| | - Zihan Li
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200433, Shanghai, China
| | - Pengliang Leng
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200433, Shanghai, China
- Shanghai Qi Zhi Institute, 41th Floor, AI Tower, No. 701 Yunjin Road, Xuhui District, 200232, Shanghai, China
| | - Xiangyu Cao
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200433, Shanghai, China
- Shanghai Qi Zhi Institute, 41th Floor, AI Tower, No. 701 Yunjin Road, Xuhui District, 200232, Shanghai, China
| | - Xingdan Sun
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 110016, Shenyang, China
| | - Tongyao Zhang
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, 030006, Taiyuan, China
| | - Xufeng Kou
- School of Information Science and Technology, ShanghaiTech University, 201210, Shanghai, China
| | - Zheng Han
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 110016, Shenyang, China
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, 030006, Taiyuan, China
| | - Faxian Xiu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200433, Shanghai, China.
- Shanghai Qi Zhi Institute, 41th Floor, AI Tower, No. 701 Yunjin Road, Xuhui District, 200232, Shanghai, China.
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, 200433, Shanghai, China.
- Shanghai Research Center for Quantum Sciences, 201315, Shanghai, China.
| | - Shaoming Dong
- State Key Laboratory of High Performance Ceramics & Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 200050, Shanghai, China.
| |
Collapse
|
4
|
Caruso R, Giovanna Ahmad H, Pal A, Piero Pepe G, Massarotti D, Blamire MG, Tafuri F. Low temperature characterization of high efficiency spin-filter Josephson junctions. EPJ WEB OF CONFERENCES 2020. [DOI: 10.1051/epjconf/202023305007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The interplay between superconducting and ferromagnetic order pa¬rameters in S/F interfaces gives rise to a wide range of peculiar properties with applications in high-efficiency computation and in the emerging field of super¬conducting spintronics. In NbN/GdN/NbN Josephson junctions, GdN barriers give unique properties due to the double insulting and ferromagnetic nature of the material, as demonstrated in previous works. Here we focus on tunneling spectroscopy of these junctions down to 0.3 K when changing the barrier thick¬ness, which contributes to complete a consistent picture on the physics of these junctions and supports the previous indications of equal-spin Cooper pairs con¬tributing to the total supercurrent of the devices.
Collapse
|