1
|
Ignatova K, Thorsteinsson EB, Jósteinsson BA, Strandqvist N, Vantaraki C, Kapaklis V, Devishvili A, Pálsson GK, Arnalds UB. Reversible exchange bias in epitaxial V 2O 3/Ni hybrid magnetic heterostructures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:495001. [PMID: 36220016 DOI: 10.1088/1361-648x/ac9946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 10/11/2022] [Indexed: 06/16/2023]
Abstract
In this work we present a temperature and angular dependent study of the structural and magnetic properties in highly crystalline V2O3/Ni/Zr magnetic heterostructure films. Our investigation focuses on the coupling between the ferromagnetic Ni layer and V2O3layer which undergoes an antiferromagnetic/paramagnetic phase transition coupled to the structural phase transition of the material at around 150 K. Structural investigations using x-ray diffraction reveal highly crystalline films of a quality which has previously not been reported in the literature. The Ni layers display an absence of in-plane magnetic anisotropy owing to the highly textured (1 1 1) layering of the Ni films on the underlying V2O3(0 0 0 1) oriented layer. During the transition we observe a strain related enhancement of the coercivity and the onset of a weak exchange bias for cooling under an external magnetic field. Heating the films to above the transition temperature, the exchange bias in the Ni is removed and can be reversed upon subsequent cooling under an inverted external magnetic field. Using temperature dependent polarized neutron reflectometry we investigate the film structure at the interface, capturing the magnetic and nuclear profiles.
Collapse
Affiliation(s)
- K Ignatova
- Science Institute, University of Iceland, Dunhaga 3, 107 Reykjavik, Iceland
| | - E B Thorsteinsson
- Science Institute, University of Iceland, Dunhaga 3, 107 Reykjavik, Iceland
| | - B A Jósteinsson
- Science Institute, University of Iceland, Dunhaga 3, 107 Reykjavik, Iceland
| | - N Strandqvist
- Department of Physics, Uppsala University, Uppsala SE-751 20, Sweden
| | - C Vantaraki
- Department of Physics, Uppsala University, Uppsala SE-751 20, Sweden
| | - V Kapaklis
- Department of Physics, Uppsala University, Uppsala SE-751 20, Sweden
| | - A Devishvili
- Department of Physics, Uppsala University, Uppsala SE-751 20, Sweden
- Institut Laue-Langevin, BP 156, 38042 Grenoble, France
| | - G K Pálsson
- Department of Physics, Uppsala University, Uppsala SE-751 20, Sweden
| | - U B Arnalds
- Science Institute, University of Iceland, Dunhaga 3, 107 Reykjavik, Iceland
| |
Collapse
|
2
|
Thorsteinsson EB, Shayestehaminzadeh S, Ingason AS, Magnus F, Arnalds UB. Controlling metal-insulator transitions in reactively sputtered vanadium sesquioxide thin films through structure and stoichiometry. Sci Rep 2021; 11:6273. [PMID: 33737525 PMCID: PMC7973816 DOI: 10.1038/s41598-021-85397-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 02/10/2021] [Indexed: 11/09/2022] Open
Abstract
We present a study of \documentclass[12pt]{minimal}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{mathrsfs}
\usepackage{upgreek}
\setlength{\oddsidemargin}{-69pt}
\begin{document}$$\hbox {V}_{2}\hbox {O}_{3}$$\end{document}V2O3 thin films grown on c-plane \documentclass[12pt]{minimal}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{mathrsfs}
\usepackage{upgreek}
\setlength{\oddsidemargin}{-69pt}
\begin{document}$$\hbox {Al}_{2}\hbox {O}_{3}$$\end{document}Al2O3 substrates by reactive dc-magnetron sputtering. Our results reveal three distinct types of films displaying different metal–insulator transitions dependent on the growth conditions. We observe a clear temperature window, spanning 200 \documentclass[12pt]{minimal}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{mathrsfs}
\usepackage{upgreek}
\setlength{\oddsidemargin}{-69pt}
\begin{document}$$^{\circ }$$\end{document}∘C, where highly epitaxial films of \documentclass[12pt]{minimal}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{mathrsfs}
\usepackage{upgreek}
\setlength{\oddsidemargin}{-69pt}
\begin{document}$$\hbox {V}_{2}\hbox {O}_{3}$$\end{document}V2O3 can be obtained wherein the transition can be tuned by controlling the amount of interstitial oxygen in the films through the deposition conditions. Although small structural variations are observed within this window, large differences are observed in the electrical properties of the films with strong differences in the magnitude and temperature of the metal–insulator transition which we attribute to small changes in the stoichiometry and local strain in the films. Altering the sputtering power we are able to tune the characteristics of the metal–insulator transition suppressing and shifting the transition to lower temperatures as the power is reduced. Combined results for all the films fabricated for the study show a preferential increase in the a lattice parameter and reduction in the c lattice parameter with reduced deposition temperature with the film deviating from a constant volume unit cell to a higher volume.
Collapse
Affiliation(s)
| | | | | | - Fridrik Magnus
- Science Institute, University of Iceland, Dunhaga 3, 107, Reykjavik, Iceland
| | - Unnar B Arnalds
- Science Institute, University of Iceland, Dunhaga 3, 107, Reykjavik, Iceland.
| |
Collapse
|
3
|
Colin J, Jamnig A, Furgeaud C, Michel A, Pliatsikas N, Sarakinos K, Abadias G. In Situ and Real-Time Nanoscale Monitoring of Ultra-Thin Metal Film Growth Using Optical and Electrical Diagnostic Tools. NANOMATERIALS (BASEL, SWITZERLAND) 2020; 10:E2225. [PMID: 33182409 PMCID: PMC7697846 DOI: 10.3390/nano10112225] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 10/30/2020] [Accepted: 11/03/2020] [Indexed: 01/08/2023]
Abstract
Continued downscaling of functional layers for key enabling devices has prompted the development of characterization tools to probe and dynamically control thin film formation stages and ensure the desired film morphology and functionalities in terms of, e.g., layer surface smoothness or electrical properties. In this work, we review the combined use of in situ and real-time optical (wafer curvature, spectroscopic ellipsometry) and electrical probes for gaining insights into the early growth stages of magnetron-sputter-deposited films. Data are reported for a large variety of metals characterized by different atomic mobilities and interface reactivities. For fcc noble-metal films (Ag, Cu, Pd) exhibiting a pronounced three-dimensional growth on weakly-interacting substrates (SiO2, amorphous carbon (a-C)), wafer curvature, spectroscopic ellipsometry, and resistivity techniques are shown to be complementary in studying the morphological evolution of discontinuous layers, and determining the percolation threshold and the onset of continuous film formation. The influence of growth kinetics (in terms of intrinsic atomic mobility, substrate temperature, deposition rate, deposition flux temporal profile) and the effect of deposited energy (through changes in working pressure or bias voltage) on the various morphological transition thicknesses is critically examined. For bcc transition metals, like Fe and Mo deposited on a-Si, in situ and real-time growth monitoring data exhibit transient features at a critical layer thickness of ~2 nm, which is a fingerprint of an interface-mediated crystalline-to-amorphous phase transition, while such behavior is not observed for Ta films that crystallize into their metastable tetragonal β-Ta allotropic phase. The potential of optical and electrical diagnostic tools is also explored to reveal complex interfacial reactions and their effect on growth of Pd films on a-Si or a-Ge interlayers. For all case studies presented in the article, in situ data are complemented with and benchmarked against ex situ structural and morphological analyses.
Collapse
Affiliation(s)
- Jonathan Colin
- Institut Pprime, UPR 3346, CNRS-Université de Poitiers-ENSMA, 11 Boulevard Marie et Pierre Curie, TSA 41123, CEDEX 9, 86073 Poitiers, France; (J.C.); (A.J.); (C.F.); (A.M.)
| | - Andreas Jamnig
- Institut Pprime, UPR 3346, CNRS-Université de Poitiers-ENSMA, 11 Boulevard Marie et Pierre Curie, TSA 41123, CEDEX 9, 86073 Poitiers, France; (J.C.); (A.J.); (C.F.); (A.M.)
- Nanoscale Engineering Division, Department of Physics, Chemistry and Biology, Linköping University, SE 581 83 Linköping, Sweden;
| | - Clarisse Furgeaud
- Institut Pprime, UPR 3346, CNRS-Université de Poitiers-ENSMA, 11 Boulevard Marie et Pierre Curie, TSA 41123, CEDEX 9, 86073 Poitiers, France; (J.C.); (A.J.); (C.F.); (A.M.)
| | - Anny Michel
- Institut Pprime, UPR 3346, CNRS-Université de Poitiers-ENSMA, 11 Boulevard Marie et Pierre Curie, TSA 41123, CEDEX 9, 86073 Poitiers, France; (J.C.); (A.J.); (C.F.); (A.M.)
| | - Nikolaos Pliatsikas
- Nanoscale Engineering Division, Department of Physics, Chemistry and Biology, Linköping University, SE 581 83 Linköping, Sweden;
| | - Kostas Sarakinos
- Nanoscale Engineering Division, Department of Physics, Chemistry and Biology, Linköping University, SE 581 83 Linköping, Sweden;
| | - Gregory Abadias
- Institut Pprime, UPR 3346, CNRS-Université de Poitiers-ENSMA, 11 Boulevard Marie et Pierre Curie, TSA 41123, CEDEX 9, 86073 Poitiers, France; (J.C.); (A.J.); (C.F.); (A.M.)
| |
Collapse
|
4
|
Hajihoseini H, Kateb M, Ingvarsson SÞ, Gudmundsson JT. Oblique angle deposition of nickel thin films by high-power impulse magnetron sputtering. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2019; 10:1914-1921. [PMID: 31598457 PMCID: PMC6774078 DOI: 10.3762/bjnano.10.186] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Accepted: 09/02/2019] [Indexed: 06/10/2023]
Abstract
Background: Oblique angle deposition is known for yielding the growth of columnar grains that are tilted in the direction of the deposition flux. Using this technique combined with high-power impulse magnetron sputtering (HiPIMS) can induce unique properties in ferromagnetic thin films. Earlier we have explored the properties of polycrystalline and epitaxially deposited permalloy thin films deposited under 35° tilt using HiPIMS and compared it with films deposited by dc magnetron sputtering (dcMS). The films prepared by HiPIMS present lower anisotropy and coercivity fields than films deposited with dcMS. For the epitaxial films dcMS deposition gives biaxial anisotropy while HiPIMS deposition gives a well-defined uniaxial anisotropy. Results: We report on the deposition of 50 nm polycrystalline nickel thin films by dcMS and HiPIMS while the tilt angle with respect to the substrate normal is varied from 0° to 70°. The HiPIMS-deposited films are always denser, with a smoother surface and are magnetically softer than the dcMS-deposited films under the same deposition conditions. The obliquely deposited HiPIMS films are significantly more uniform in terms of thickness. Cross-sectional SEM images reveal that the dcMS-deposited film under 70° tilt angle consists of well-defined inclined nanocolumnar grains while grains of HiPIMS-deposited films are smaller and less tilted. Both deposition methods result in in-plane isotropic magnetic behavior at small tilt angles while larger tilt angles result in uniaxial magnetic anisotropy. The transition tilt angle varies with deposition method and is measured around 35° for dcMS and 60° for HiPIMS. Conclusion: Due to the high discharge current and high ionized flux fraction, the HiPIMS process can suppress the inclined columnar growth induced by oblique angle deposition. Thus, the ferromagnetic thin films obliquely deposited by HiPIMS deposition exhibit different magnetic properties than dcMS-deposited films. The results demonstrate the potential of the HiPIMS process to tailor the material properties for some important technological applications in addition to the ability to fill high aspect ratio trenches and coating on cutting tools with complex geometries.
Collapse
Affiliation(s)
| | - Movaffaq Kateb
- Science Institute, University of Iceland, Dunhaga 3, IS-107 Reykjavik, Iceland
| | | | - Jon Tomas Gudmundsson
- Science Institute, University of Iceland, Dunhaga 3, IS-107 Reykjavik, Iceland
- Department of Space and Plasma Physics, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, SE-100 44, Stockholm, Sweden
| |
Collapse
|
5
|
Pedrosa P, Cote JM, Martin N, Arab Pour Yazdi M, Billard A. In situ electrical resistivity measurements of vanadium thin films performed in vacuum during different annealing cycles. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:025105. [PMID: 28249524 DOI: 10.1063/1.4974847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The present study describes a sputtering and in situ vacuum electrical resistivity setup that allows a more efficient sputtering-oxidation coupling process for the fabrication of oxide compounds like vanadium dioxide, VO2. After the sputtering deposition of pure V thin films, the proposed setup enables the sample holder to be transferred from the sputtering to the in situ annealing + resistivity chamber without venting the whole system. The thermal oxidation of the V films was studied by implementing two different temperature cycles up to 550 °C, both in air (using a different resistivity setup) and vacuum conditions. Main results show that the proposed system is able to accurately follow the different temperature setpoints, presenting clean and low-noise resistivity curves. Furthermore, it is possible to identify the formation of different vanadium oxide phases in air, taking into account the distinct temperature cycles used. The metallic-like electrical properties of the annealed coatings are maintained in vacuum whereas those heated in air produce a vanadium oxide phase mixture.
Collapse
Affiliation(s)
- Paulo Pedrosa
- Institut FEMTO-ST, UMR 6174 CNRS, Université Bourgogne Franche-Comté, 15B Avenue des Montboucons, 25030 Cedex Besançon, France
| | - Jean-Marc Cote
- Institut FEMTO-ST, UMR 6174 CNRS, Université Bourgogne Franche-Comté, 15B Avenue des Montboucons, 25030 Cedex Besançon, France
| | - Nicolas Martin
- Institut FEMTO-ST, UMR 6174 CNRS, Université Bourgogne Franche-Comté, 15B Avenue des Montboucons, 25030 Cedex Besançon, France
| | - Mohammad Arab Pour Yazdi
- Institut FEMTO-ST, UMR 6174 CNRS, UTBM, Université Bourgogne Franche-Comté, F-90010 Cedex Belfort, France
| | - Alain Billard
- Institut FEMTO-ST, UMR 6174 CNRS, UTBM, Université Bourgogne Franche-Comté, F-90010 Cedex Belfort, France
| |
Collapse
|
6
|
Colin JJ, Diot Y, Guerin P, Lamongie B, Berneau F, Michel A, Jaouen C, Abadias G. A load-lock compatible system for in situ electrical resistivity measurements during thin film growth. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:023902. [PMID: 26931861 DOI: 10.1063/1.4940933] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
An experimental setup designed for in situ electrical resistance measurement during thin film growth is described. The custom-built sample holder with a four-point probe arrangement can be loaded into a high-vacuum magnetron sputter-deposition chamber through a load-lock transfer system, allowing measurements on series of samples without venting the main chamber. Electrical contact is ensured with circular copper tracks inserted in a Teflon plate on a mounting holder station inside the deposition chamber. This configuration creates the possibility to measure thickness-dependent electrical resistance changes with sub-monolayer resolution and is compatible with use of sample rotation during growth. Examples are presented for metallic films with high adatom mobility growing in a Volmer-Weber mode (Ag and Pd) as well as for refractory metal (Mo) with low adatom mobility. Evidence for an amorphous-to-crystalline phase transition at a film thickness of 2.6 nm is reported during growth of Mo on an amorphous Si underlayer, supporting previous findings based on in situ wafer curvature measurements.
Collapse
Affiliation(s)
- J J Colin
- Département Physique et Mécanique des Matériaux, Institut Pprime, UPR 3346, CNRS-Université de Poitiers, SP2MI Téléport 2, F86962 Chasseneuil-Futuroscope Cedex, France
| | - Y Diot
- Département Physique et Mécanique des Matériaux, Institut Pprime, UPR 3346, CNRS-Université de Poitiers, SP2MI Téléport 2, F86962 Chasseneuil-Futuroscope Cedex, France
| | - Ph Guerin
- Département Physique et Mécanique des Matériaux, Institut Pprime, UPR 3346, CNRS-Université de Poitiers, SP2MI Téléport 2, F86962 Chasseneuil-Futuroscope Cedex, France
| | - B Lamongie
- Département Physique et Mécanique des Matériaux, Institut Pprime, UPR 3346, CNRS-Université de Poitiers, SP2MI Téléport 2, F86962 Chasseneuil-Futuroscope Cedex, France
| | - F Berneau
- Département Physique et Mécanique des Matériaux, Institut Pprime, UPR 3346, CNRS-Université de Poitiers, SP2MI Téléport 2, F86962 Chasseneuil-Futuroscope Cedex, France
| | - A Michel
- Département Physique et Mécanique des Matériaux, Institut Pprime, UPR 3346, CNRS-Université de Poitiers, SP2MI Téléport 2, F86962 Chasseneuil-Futuroscope Cedex, France
| | - C Jaouen
- Département Physique et Mécanique des Matériaux, Institut Pprime, UPR 3346, CNRS-Université de Poitiers, SP2MI Téléport 2, F86962 Chasseneuil-Futuroscope Cedex, France
| | - G Abadias
- Département Physique et Mécanique des Matériaux, Institut Pprime, UPR 3346, CNRS-Université de Poitiers, SP2MI Téléport 2, F86962 Chasseneuil-Futuroscope Cedex, France
| |
Collapse
|