Research

10 pages, 3219 KiB

Open AccessArticle

Influence of the NiFe/Cu/NiFe Structure Dimensions and Position in External Magnetic Field on Resistance Changes under the Magnetoresistance Effect

by Jakub Kisała, Andrzej Kociubiński and Elżbieta Jartych

Materials 2023, 16(13), 4810; https://0-doi-org.brum.beds.ac.uk/10.3390/ma16134810 - 04 Jul 2023

Viewed by 695

Abstract

The subject of this work is NiFe/Cu/NiFe thin-film structures made by magnetron sputtering and showing the phenomenon of magnetoresistance. Three series of samples differing in spatial dimensions and thickness of the Cu spacer were produced. During the sputtering process, an external magnetic field [...] Read more.

The subject of this work is NiFe/Cu/NiFe thin-film structures made by magnetron sputtering and showing the phenomenon of magnetoresistance. Three series of samples differing in spatial dimensions and thickness of the Cu spacer were produced. During the sputtering process, an external magnetic field of approx. 10 mT was applied to the substrate. Measurements of the resistance of the structures were carried out in the field of neodymium magnets in three different positions of the sample in relation to the direction of the field. The measurements allowed us to indicate in which position the structures of different series achieved the greatest changes in resistance. For each of the three series of layer systems, the nature of changes in the determined coefficient of giant magnetoresistance ΔR/R remained similar, while for the series with the smallest copper thickness (2.5 nm), the coefficient reached the highest value of about 2.7‰. In addition, impedance measurements were made for the structures of each series in the frequency range from 100 Hz to 100 kHz. For series with a thinner copper layer, a decrease in impedance values was observed in the 10–100 kHz range. Full article

(This article belongs to the Special Issue Advanced Thin Films: Technology, Properties and Multiple Applications)

► Show Figures

Figure 1

15 pages, 11551 KiB

Open AccessArticle

Influence of Annealing on Mechanical Behavior of Alumina-Tantala Nanolaminates

by Helle-Mai Piirsoo, Taivo Jõgiaas, Kaupo Kukli and Aile Tamm

Materials 2023, 16(8), 3207; https://0-doi-org.brum.beds.ac.uk/10.3390/ma16083207 - 19 Apr 2023

Viewed by 741

Abstract

Mechanical properties of thin films are significant for the applicability of nanodevices. Amorphous Al₂O₃-Ta₂O₅ double and triple layers were atomic layer-deposited to the thickness of 70 nm with constituent single-layer thicknesses varying from 40 to 23 [...] Read more.

Mechanical properties of thin films are significant for the applicability of nanodevices. Amorphous Al₂O₃-Ta₂O₅ double and triple layers were atomic layer-deposited to the thickness of 70 nm with constituent single-layer thicknesses varying from 40 to 23 nm. The sequence of layers was alternated and rapid thermal annealing (700 and 800 °C) was implemented on all deposited nanolaminates. Annealing caused changes in the microstructure of laminates dependent on their layered structure. Various shapes of crystalline grains of orthorhombic Ta₂O₅ were formed. Annealing at 800 °C resulted in hardening up to 16 GPa (~11 GPa prior to annealing) in double-layered laminate with top Ta₂O₅ and bottom Al₂O₃ layers, while the hardness of all other laminates remained below 15 GPa. The elastic modulus of annealed laminates depended on the sequence of layers and reached up to 169 GPa. The layered structure of the laminate had a significant influence on the mechanical behavior after annealing treatments. Full article

(This article belongs to the Special Issue Advanced Thin Films: Technology, Properties and Multiple Applications)

► Show Figures

Figure 1

10 pages, 2296 KiB

Open AccessArticle

Multitarget Reactive Magnetron Sputtering towards the Production of Strontium Molybdate Thin Films

by Mindaugas Andrulevičius, Evgenii Artiukh, Gunnar Suchaneck, Sitao Wang, Nikolai A. Sobolev, Gerald Gerlach, Asta Tamulevičienė, Brigita Abakevičienė and Sigitas Tamulevičius

Materials 2023, 16(6), 2175; https://0-doi-org.brum.beds.ac.uk/10.3390/ma16062175 - 08 Mar 2023

Cited by 1 | Viewed by 1107

Abstract

X-ray photoelectron spectroscopy was used to study the direct synthesis of strontium and molybdenum oxide thin films deposited by multitarget reactive magnetron sputtering (MT-RMS). Sr and Mo targets with a purity of 99.9% and 99.5%, respectively, were co-sputtered in an argon–oxygen gas mixture. [...] Read more.

X-ray photoelectron spectroscopy was used to study the direct synthesis of strontium and molybdenum oxide thin films deposited by multitarget reactive magnetron sputtering (MT-RMS). Sr and Mo targets with a purity of 99.9% and 99.5%, respectively, were co-sputtered in an argon–oxygen gas mixture. The chamber was provided with an oxygen background flow plus an additional controlled oxygen supply to each of the targets. We demonstrate that variation in the power applied to the Mo target during MT-RMS enables the production of strontium and molybdenum oxide films with variable concentrations of Mo atoms. Both molybdenum and strontium were found in the oxidized state, and no metallic peaks were detected. The deconvoluted high-resolution XPS spectra of molybdenum revealed the presence of several Mo 3d peaks, which indicates molybdenum bonds in a lower valence state. Contrary to the Mo spectra, the high-resolution strontium Sr 3d spectra for the same samples were very similar, and no additional peaks were detected. Full article

(This article belongs to the Special Issue Advanced Thin Films: Technology, Properties and Multiple Applications)

► Show Figures

Figure 1

13 pages, 4154 KiB

Open AccessArticle

Magnetoelectric MEMS Magnetic Field Sensor Based on a Laminated Heterostructure of Bidomain Lithium Niobate and Metglas

by Andrei V. Turutin, Elena A. Skryleva, Ilya V. Kubasov, Filipp O. Milovich, Alexander A. Temirov, Kirill V. Raketov, Aleksandr M. Kislyuk, Roman N. Zhukov, Boris R. Senatulin, Victor V. Kuts, Mikhail D. Malinkovich, Yuriy N. Parkhomenko and Nikolai A. Sobolev

Materials 2023, 16(2), 484; https://0-doi-org.brum.beds.ac.uk/10.3390/ma16020484 - 04 Jan 2023

Cited by 5 | Viewed by 1940

Abstract

Non-contact mapping of magnetic fields produced by the human heart muscle requires the application of arrays of miniature and highly sensitive magnetic field sensors. In this article, we describe a MEMS technology of laminated magnetoelectric heterostructures comprising a thin piezoelectric lithium niobate single [...] Read more.

Non-contact mapping of magnetic fields produced by the human heart muscle requires the application of arrays of miniature and highly sensitive magnetic field sensors. In this article, we describe a MEMS technology of laminated magnetoelectric heterostructures comprising a thin piezoelectric lithium niobate single crystal and a film of magnetostrictive metglas. In the former, a ferroelectric bidomain structure is created using a technique developed by the authors. A cantilever is formed by microblasting inside the lithium niobate crystal. Metglas layers are deposited by magnetron sputtering. The quality of the metglas layers was assessed by XPS depth profiling and TEM. Detailed measurements of the magnetoelectric effect in the quasistatic and dynamic modes were performed. The magnetoelectric coefficient |α₃₂| reaches a value of 492 V/(cm·Oe) at bending resonance. The quality factor of the structure was Q = 520. The average phase amounted to 93.4° ± 2.7° for the magnetic field amplitude ranging from 12 to 100 pT. An AC magnetic field detection limit of 12 pT at a resonance frequency of 3065 Hz was achieved which exceeds by a factor of 5 the best value for magnetoelectric MEMS lead-free composites reported in the literature. The noise level of the magnetoelectric signal was 0.47 µV/Hz^1/2. Ways to improve the sensitivity of the developed sensors to the magnetic field for biomedical applications are indicated. Full article

(This article belongs to the Special Issue Advanced Thin Films: Technology, Properties and Multiple Applications)

► Show Figures

Figure 1

12 pages, 13029 KiB

Open AccessArticle

Study of Internal Stress in Conductive and Dielectric Thick Films

by Jiri Hlina, Jan Reboun, Martin Janda and Ales Hamacek

Materials 2022, 15(23), 8686; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15238686 - 06 Dec 2022

Cited by 1 | Viewed by 1199

Abstract

This paper is focused on the study of internal stress in thick films used in hybrid microelectronics. Internal stress in thick films arises after firing and during cooling due to the differing coefficients of thermal expansion in fired film and ceramic substrates. Different [...] Read more.

This paper is focused on the study of internal stress in thick films used in hybrid microelectronics. Internal stress in thick films arises after firing and during cooling due to the differing coefficients of thermal expansion in fired film and ceramic substrates. Different thermal expansions cause deflection of the substrate and in extreme cases, the deflection can lead to damage of the substrate. Two silver pastes and two dielectric pastes, as well as their combinations, were used for the experiments, and the internal stress in the thick films was investigated using the cantilever method. Further experiments were also focused on internal stress changes during the experiment and on the influence of heat treatment (annealing) on internal stress. The results were correlated with the morphology of the fired thick films. The internal stress in the thick films was in the range of 8 to 21 MPa for metallic films and in the range from 12 to 16 MPa for dielectric films. It was verified that the cantilever method can be successfully used for the evaluation of internal stress in thick films. It was also found that the values of deflection and internal stress are not stable after firing, and they can change over time, mainly for metallic thick films. Full article

(This article belongs to the Special Issue Advanced Thin Films: Technology, Properties and Multiple Applications)

► Show Figures

Figure 1

17 pages, 2036 KiB

Open AccessArticle

Production and Properties of the Porous Layer Obtained by the Electrochemical Method on the Surface of Austenitic Steel

by Agnieszka Ossowska, Jacek Ryl and Tomasz Sternicki

Materials 2022, 15(3), 949; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15030949 - 26 Jan 2022

Cited by 5 | Viewed by 2131

Abstract

The growing demand for implants has seen increasing interest in the introduction of new technologies and surface modification methods of metal biomaterials. This research aimed to produce and characterize a porous layer grown on austenitic stainless steel 316L, obtained via the anodization process [...] Read more.

The growing demand for implants has seen increasing interest in the introduction of new technologies and surface modification methods of metal biomaterials. This research aimed to produce and characterize a porous layer grown on austenitic stainless steel 316L, obtained via the anodization process near the micro-arc oxidation, i.e., low voltage micro-arc oxidation (LVMAO). The discussed layer significantly influences the properties of metallic biomedical materials. The surface topography, layer thickness, surface roughness, pore diameter, elemental composition, crystal structure, and surface wettability were assessed for all anodized layers, together with the resultant corrosion resistance. Attention was paid to the influence of the process parameters that affect the specification of the produced layer. The obtained results showed surface development and different sized pores in the modified layers, as well as an increase in corrosion resistance in the Ringer’s solution. Full article

(This article belongs to the Special Issue Advanced Thin Films: Technology, Properties and Multiple Applications)

► Show Figures

Figure 1

15 pages, 2463 KiB

Open AccessArticle

Study of the Layer-Type BST Thin Film with X-ray Diffraction and X-ray Photoelectron Spectroscopy

by Agata Lisińska-Czekaj and Dionizy Czekaj

Materials 2022, 15(2), 578; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15020578 - 13 Jan 2022

Cited by 1 | Viewed by 1449

Abstract

In the present paper, results of X-ray photoelectron studies of electroceramic thin films of barium strontium titanate, Ba_1−xSr_xTiO₃ (BST), composition deposited on stainless-steel substrates are presented. The thin films were prepared by the sol-gel method. A spin-coating deposition [...] Read more.

In the present paper, results of X-ray photoelectron studies of electroceramic thin films of barium strontium titanate, Ba_1−xSr_xTiO₃ (BST), composition deposited on stainless-steel substrates are presented. The thin films were prepared by the sol-gel method. A spin-coating deposition of BST layers with different chemical compositions was utilized so the layer-type structure of (0-2) connectivity was formed. After the deposition, the thin-film samples were heated in air atmosphere at temperature T = 700 °C for 1 h. The surfaces of BST thin films subjected to thermal treatment were studied by X-ray diffraction. X-ray diffraction measurements confirmed the perovskite-type phase for all grown thin-film samples. The oxidation states of the elements were examined by the X-ray photoelectron spectroscopy method. X-ray photoelectron spectroscopy survey spectra as well as high-resolution spectra (photo-peaks) of the main metallic elements, such as Ti, Ba, and Sr, were compared for the layer-type structures, differing in the deposition sequence of the barium strontium titanate layers constituting the BST thin film. Full article

(This article belongs to the Special Issue Advanced Thin Films: Technology, Properties and Multiple Applications)

► Show Figures

Figure 1

11 pages, 30200 KiB

Open AccessEditor’s ChoiceArticle

Effects of Iodine Doping on Electrical Characteristics of Solution-Processed Copper Oxide Thin-Film Transistors

by Hyeonju Lee, Xue Zhang, Bokyung Kim, Jin-Hyuk Bae and Jaehoon Park

Materials 2021, 14(20), 6118; https://0-doi-org.brum.beds.ac.uk/10.3390/ma14206118 - 15 Oct 2021

Cited by 5 | Viewed by 2152

Abstract

In order to implement oxide semiconductor-based complementary circuits, the improvement of the electrical properties of p-type oxide semiconductors and the performance of p-type oxide TFTs is certainly required. In this study, we report the effects of iodine doping on the structural and electrical [...] Read more.

In order to implement oxide semiconductor-based complementary circuits, the improvement of the electrical properties of p-type oxide semiconductors and the performance of p-type oxide TFTs is certainly required. In this study, we report the effects of iodine doping on the structural and electrical characteristics of copper oxide (CuO) semiconductor films and the TFT performance. The CuO semiconductor films were fabricated using copper(II) acetate hydrate as a precursor to solution processing, and iodine doping was performed using vapor sublimated from solid iodine. Doped iodine penetrated the CuO film through grain boundaries, thereby inducing tensile stress in the film and increasing the film’s thickness. Iodine doping contributed to the improvement of the electrical properties of the solution-processed CuO semiconductor including increases in Hall mobility and hole-carrier concentration and a decrease in electrical resistivity. The CuO TFTs exhibited a conduction channel formation by holes, that is, p-type operation characteristics, and the TFT performance improved after iodine doping. Iodine doping was also found to be effective in reducing the counterclockwise hysteresis in the transfer characteristics of CuO TFTs. These results are explained by physicochemical reactions in which iodine replaces oxygen vacancies and oxygen atoms through the formation of iodide anions in CuO. Full article

(This article belongs to the Special Issue Advanced Thin Films: Technology, Properties and Multiple Applications)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Advanced Thin Films: Technology, Properties and Multiple Applications

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Published Papers (8 papers)

Research

Further Information

Guidelines

MDPI Initiatives

Follow MDPI