Article
Chemistry, Physical
Nalin Prashant Poddar, J. Arout Chelvane, N. D. Vara Prasad, M. Manivel Raja
Summary: In this paper, the relationship between the structure-magnetic microstructure and magnetic properties of sputtered Fe-Co-Al thin films at different thicknesses is investigated. The results show that the crystallinity and particle size of the films increase with the increase in film thickness. The magnetic properties, including saturation magnetization and coercivity, change with the film thickness due to the observed changes in the magnetic microstructure. Evaluation: 8/10.
SURFACES AND INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
D-Y Park, N. Myung
Summary: CoPt and CoPtP thin films were synthesized by direct current aqueous electrodeposition from weak alkaline solutions. The composition of the films was adjusted by varying electrodeposition parameters, resulting in different microstructures and magnetic properties.
FRONTIERS IN CHEMISTRY
(2021)
Article
Physics, Condensed Matter
Moumita Naskar, Muktish Acharyya
Summary: The study focused on the reversal of magnetisation in a two-dimensional Spin-1 Blume-Capel ferromagnet, revealing an exponential dependence between reversal time and single-site anisotropy strength, as well as a linear relationship between saturated magnetisation after reversal and the strength of anisotropy.
EUROPEAN PHYSICAL JOURNAL B
(2021)
Article
Physics, Applied
A. Roman, A. Lopez Pedroso, K. Bouzehouane, J. E. Gomez, A. Butera, M. H. Aguirre, M. Medeiros Soares, C. Garcia, L. B. Steren
Summary: The competition between shape and perpendicular magnetic anisotropies in magnetic thin films leads to unconventional magnetic behaviors. In ferromagnetic thin films, the out-of-plane component of magnetic anisotropy can induce a transition from planar to stripe-like magnetic domains above a critical thickness, tc. This article presents a detailed study of the magnetization switching mechanism in FePt thin films where this phenomenon is observed. Micromagnetic simulations and experiments show that below tc, the reversal mechanism is well described by the two-phase model, while above this thickness, the magnetization within each stripe reverses through coherent rotation. The out-of-plane component and its temperature dependence of the magnetic anisotropy were also analyzed, indicating that substrate-induced strains are responsible for the abnormal coercive field behavior observed for FePt films with t > tc.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Article
Chemistry, Inorganic & Nuclear
Henrique C. Silva Junior, Heloisa N. S. Menezes, Glaucio B. Ferreira, Guilherme P. Guedes
Summary: This study demonstrates the accuracy and speed of deep neural networks (DNNs) in estimating the axial magnetic anisotropy (D) values for single-ion magnets. By using a curated database of cobalt(II) compounds, the DNN achieved significantly higher accuracy and speed compared to density functional theory (DFT) methods. The findings suggest the potential for DNNs to predict anisotropy in larger molecules, even when trained on smaller ligands.
INORGANIC CHEMISTRY
(2023)
Article
Physics, Applied
Satoshi Sugimoto, Yukiko K. Takahashi, Shinya Kasai
Summary: The spin reorientation in rare-earth intermetallics and its modulation of magnetocrystalline anisotropy provide a research platform for realizing room-temperature topological magnetic textures.
APPLIED PHYSICS LETTERS
(2022)
Article
Chemistry, Physical
Bowen Yang, Yin Min Goh, Suk Hyun Sung, Gaihua Ye, Sananda Biswas, David A. S. Kaib, Ramesh Dhakal, Shaohua Yan, Chenghe Li, Shengwei Jiang, Fangchu Chen, Hechang Lei, Rui He, Roser Valenti, Stephen M. Winter, Robert Hovden, Adam W. Tsen
Summary: The authors investigate the magnetic anisotropy in monolayer RuCl3 and observe a transition from easy-plane to easy-axis due to in-plane distortions of Cl atoms. This finding is important for realizing a quantum spin liquid. The study provides insights into the possibility of exploring Kitaev physics in a true two-dimensional limit.
Article
Chemistry, Multidisciplinary
Song Lin Zhang, Xue Feng Lu, Zhi-Peng Wu, Deyan Luan, Xiong Wen (David) Lou
Summary: In this study, ultrafine PtCo alloy nanoparticles attached on porous nitrogen-doped carbon nanotubes were synthesized using a metal-organic framework-assisted pyrolysis-replacement-reorganization approach. The resulting electrocatalyst exhibited outstanding activity and stability in the hydrogen evolution reaction due to the unique structure and diversified active sites induced by alloying.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Materials Science, Multidisciplinary
S. Al Risi, R. Sbiaa
Summary: Investigation of multilayers consisting of [Co/Ni(tNi)/Co/Pt](x4) with varying Ni insertion layer thicknesses revealed that they exhibit perpendicular magnetic anisotropy. Compared to (Co/Ni)(x8) multilayers, the nucleation field and magnetic coercivity of [Co/Ni(t)/Co/Pt](x4) multilayers were found to be lower and decreased with Ni thickness. The insertion of very thin Ni in (Co/Pt) multilayers provides a way to optimize magnetic properties and adjust domain size for nanowire-based devices.
CURRENT APPLIED PHYSICS
(2022)
Article
Chemistry, Physical
S. Goswami, P. Gupta, S. Bedanta, M. Chakraborty, D. De
Summary: This article reports exchange bias (EB) and memory effect in nanocrystalline CoCr2O4, with results showing that these effects are caused by inherent magnetic inhomogeneity rather than surface effects.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Chemistry, Physical
Victor K. Belyaev, Dmitry Murzin, Jose C. Martinez-Garcia, Montserrat Rivas, Nikolay V. Andreev, Aleksei G. Kozlov, Aleksei Yu. Samardak, Alexey V. Ognev, Alexander S. Samardak, Valeria Rodionova
Summary: A fabrication approach of a magnonic crystal with step-like hysteresis behavior based on uniform non-monotonous iron layer made by shadow deposition on a preconfigured substrate is reported. The origin of the step-like hysteresis loop behavior is studied and validated with various methods, including First-Order Reversal Curves (FORC) diagram analysis and magnetic microstructure dynamics measurements. The proposed fabrication method allows for control of the magnonic crystal's band structure by changing the external magnetic field.
Article
Chemistry, Analytical
Mustafa Erkovan, Caner Deger, Susana Cardoso, Necmettin Kilinc
Summary: This study investigates the feasibility of using Pt and PtCo alloy ultrathin films as hydrogen gas sensors to reduce costs. The hydrogen-sensing properties of the ultrathin films are evaluated, and the results show that PtCo alloy films have better response time compared to pure Pt films, but lower sensor response.
Article
Chemistry, Physical
Qizhong Zhao, Fanghua Tian, Tieyan Chang, Kaiyan Cao, Dingchen Wang, Yin Zhang, Chao Zhou, Xiaoqin Ke, Wenliang Zuo, Yu Wang, Sen Yang, Xiaoping Song
Summary: In this study, the magnetization reversal phenomenon in the Ni20Mn3B6 alloy was investigated at low applied fields, revealing two compensation temperatures. The first temperature is attributed to competition between Mn atoms at different positions, while the second arises from moment rotation to satisfy Zeeman energy. This phenomenon enables tunable switching of magnetization between positive and negative values, providing potential applications in spintronic devices and magnetic storage materials.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Physics, Applied
James Harris, Zhaoyuan Leong, Peng Gong, Juan Cornide, Charlotte Pughe, Thomas Hansen, Aris Quintana-Nedelcos, Richard Rowan-Robinson, Ulf Dahlborg, Monique Calvo-Dahlborg, Russell Goodall, Mark Rainforth, Nicola Morley
Summary: The study investigated the structural, magnetic, and magneto-caloric effects of FCC alloys CoFeNiCr(y)Cu(x), revealing the different impact of Cu and Cr additions on these properties. By slightly reducing the Cr content, the Curie temperature, saturation magnetization, and refrigerant capacity of the alloys can be increased.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Chemistry, Physical
Xu Xu, Haoyang Huang, Lichuan Jin, Tianlong Wen, Yulong Liao, Xiaoli Tang, Yuanxun Li, Zhiyong Zhong
Summary: Ni80Fe20 (NiFe) films were deposited on periodically rippled Al2O3 substrates by two different template oblique angle deposition (OAD) processes at various oblique deposition angles alpha (0 degrees <= alpha <= 60 degrees). The disparate in-plane uniaxial magnetic anisotropy (UMA) caused by the two template deposition processes of films was revealed by magneto-optical Kerr effect (MOKE) loops and ferromagnetic resonance (FMR) measurements. The analysis of Transmission electron microscopy images indicated that this was related to the different micromorphology of the films due to the two template deposition processes. The angle between substrates' ripple direction and the material flow incident direction would strongly influence the micromorphology and the induced in-plane UMA field of films.
SURFACES AND INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Peter Swekis, Aleksandr S. Sukhanov, Yi-Cheng Chen, Andrei Gloskovskii, Gerhard H. Fecher, Ioannis Panagiotopoulos, Jorg Sichelschmidt, Victor Ukleev, Anton Devishvili, Alexei Vorobiev, Dmytro S. Inosov, Sebastian T. B. Goennenwein, Claudia Felser, Anastasios Markou
Summary: This study investigates the structural, magnetic, and electronic properties of magnetic Weyl semimetal thin films of Co2MnGa, revealing the impact of film thickness on structural and magnetic properties, and providing experimental insights into the electronic and magnetic properties of magnetic Weyl semimetal thin films.
Article
Instruments & Instrumentation
Andrew J. C. Dennison, Anton Devishvili, Philipp Gutfreund, Robert Cubitt, Alexei Vorobiev, Hartmut Zabel, Max Wolff
Summary: Graphite intercalation compounds (GICs) are layered materials suitable for use as monochromators for cold neutrons. Different stages of GICs have specific d-spacing, and impurities and stage contamination can complicate neutron reflectometry data analysis. GIC crystals can be characterized efficiently by time-of-flight neutron diffraction, providing a quantifiable measure of the reflected wavelength spectrum to ensure robustness of reflectometry measurements.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2021)
Article
Physics, Applied
Dmitrii Moldarev, Levin Stolz, Marcos V. Moro, Sigurbjorn M. Adalsteinsson, Ioan-Augustin Chioar, Smagul Zh. Karazhanov, Daniel Primetzhofer, Max Wolff
Summary: The study shows the dependence of the photochromic effect on environment and triggering light, with the first darkening/bleaching cycle of freshly grown films accompanied by the release of weakly bound hydrogen. There is no further exchange of material with the environment in consecutive photochromic cycles. Moreover, the kinetics of bleaching is reported to be dependent on the gas environment after darkening with light of energies below the optical bandgap of the film.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Materials Science, Multidisciplinary
A. Mourkas, A. Zarlaha, N. Kourkoumelis, I Panagiotopoulos
Summary: Finite element micromagnetics are utilized to simulate vortex and onion states on permalloy spherical shells with different curvatures. The study shows that as curvature increases, vortex states become more favorable at smaller sizes, and stronger in-plane fields are required to destabilize vortex states and transform them into onion states at larger curvatures.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Apurve Saini, Katharina Theis-Broehl, Alexandros Koutsioubas, Kathryn L. Krycka, Julie A. Borchers, Max Wolff
Summary: The study investigates the assembly of magnetite nanoparticles in water-based ferrofluids near silicon substrates with different functionalization, showing that a magnetic field only promotes self-assembly when a seed layer is formed on the silicon substrate.
Article
Chemistry, Multidisciplinary
Angelos Mourkas, Angeliki Zarlaha, Nikolaos Kourkoumelis, Ioannis Panagiotopoulos
Summary: The impact of magnetic fields on the spatial arrangement of superparamagnetic nanospheres is explored, introducing long range magnetic dipolar interactions. Different assembly characteristics are observed with different methods and field directions. Perfect hexagonal arrays, directional patterns, and 3D-accumulation are obtained under specific conditions.
Article
Physics, Applied
E. Hourdakis, A. Kaidatzis, D. Niarchos
Summary: A novel concept for a self-powered photodetector is introduced, which is cost effective and can be easily integrated with Si electronics. The device operates based on the shadow effect and exhibits anisotropic behavior in diodes under illumination, resulting in a measurable open circuit voltage and short circuit current. The device's open circuit voltage has a linear term with respect to illumination power due to the presence of built-in parallel resistance, in addition to the logarithmic term in Schottky solar cells.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Energy & Fuels
Wen Huang, Xin Xiao, Parker Steichen, Sotirios A. Droulias, Martin Brischetto, Max Wolff, Xing'ao Li, Bjorgvin Hjorvarsson
Summary: The proximity effects on hydrogen absorption in ultra-thin vanadium layers were investigated through light transmission and electron scattering. The influence of these effects on the finite-size scaling of critical temperatures was attributed to variations of dead layers in the vanadium. Additionally, changes in excess resistivity confirmed the proximity effects on hydrogen absorption.
Article
Physics, Multidisciplinary
Kristina Komander, Tuan Tran, Jitendra Saha, Marcos Moro, Gunnar K. Palsson, Max Wolff, Daniel Primetzhofer
Summary: This study accurately locates the position and vibrational amplitude of hydrogen in the single crystalline Fe/V superstructures using ion channeling and nuclear reaction analysis.
PHYSICAL REVIEW LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Suraya Kazi, Dmitrii Moldarev, Marcos V. Moro, Daniel Primetzhofer, Max Wolff
Summary: Oxygen-containing yttrium hydride (YHO) exhibits both photochromic and photoconductive properties. Polycrystalline YHO thin films are deposited on glass substrates through reactive magnetron sputtering, and their optical and electrical properties are studied under illumination. The maximum photoconductive response is observed in samples with photochromism, and this effect is triggered by light above a certain cutoff energy and is stronger with shorter wavelengths. The slow recovery of optical transmission and electrical transport after illumination suggests a non-electronic underlying process, possibly involving local hydrogen diffusion.
PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS
(2023)
Article
Instruments & Instrumentation
Dmitrii Moldarev, Kristina Komander, Radek Holenak, Max Wolff, Daniel Primetzhofer
Summary: This article presents a new analytical instrument that can study the optical properties of materials in different gaseous environments at room and controlled elevated temperatures. The instrument consists of a vacuum chamber with temperature and pressure controllers, a heating band, and a residual gas analyzer, and is connected to a gas feeding line. Two transparent view ports allow for optical transmission and pump-probe spectroscopy. The capabilities of the instrument are demonstrated through two experiments involving photochromic films and hydrogen absorption.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2023)
Article
Materials Science, Multidisciplinary
E. Pitthan, C. Cupak, M. Fellinger, M. V. Moro, S. Kioumourtzoglou, D. Moldarev, M. Wolff, F. Aumayr, D. Primetzhofer
Summary: We investigated the formation of YHO and GdHO thin films by reactive e(-)-beam evaporation using in-situ and real-time monitoring. The mass changes during deposition, oxidation, and illumination were continuously measured by a highly sensitive quartz crystal microbalance, while the chemical composition and depth profiles were analyzed by ion beam measurement. The results showed the strong reactivity of freshly deposited YHx and GdHx films, and the oxidation rate was found to be dependent on the O-2 pressure. The study also discussed the response of the system under ion beam irradiation and in-situ illumination. A quantitative agreement of less than 2% was observed between the two techniques, demonstrating the consistency and sensitivity of the approach.
Article
Physics, Multidisciplinary
Christos Thanos, Ioannis Panagiotopoulos
Summary: Micromagnetic simulations are used to study resonances and microwave assisted magnetic switching (MAS) in two-phase Co/CoPt nanowires. The nucleation, interfacial domain wall pinning, and propagation processes are well distinguished and play a role in the system. The coupling strength varies to cover different hysteresis curves. Interfacial resonances play an important role in MAS, allowing for optimal conditions with low MAS frequencies and dc applied fields while balancing low field usage and short reversal time.
Article
Chemistry, Physical
Hauke Carstensen, Anne Kramer, Vassilios Kapaklis, Max Wolff
Summary: In this study, the self-assembly of branching-chain networks and crystals in a binary colloidal system with tunable interactions was investigated. Particle positions were extracted from microscopy images and order parameters were determined through image processing and statistical analysis. Phase diagrams were constructed based on particle density, ratio, and interaction, and computer simulations were used to complement the experimental results. A region in the phase diagram was identified where symmetric bead ratios and interactions promoted the formation of percolated structures.
Article
Materials Science, Multidisciplinary
P. Ntetsika, G. Mitrikas, G. Litsardakis, I Panagiotopoulos
Summary: In this study, two series of multilayers were studied using cavity FMR. The resonance fields of the modes excited by different rf field directions were investigated, and it was found that the resonance fields of the pure optical modes were lower than expected due to the existence of hybridized mixed modes. Micromagnetic simulations showed that the inhomogeneous magnetization profile along the multilayer thickness was responsible for the mode mixing.
MATERIALS ADVANCES
(2022)
