Review
Chemistry, Multidisciplinary
Tomasz Blachowicz, Andrea Ehrmann, Martin Wortmann
Summary: Exchange bias is a unidirectional anisotropy observed in ferromagnetic/antiferromagnetic systems, leading to asymmetric hysteresis loops and shifts. Despite its applications in spintronics, the origin of exchange bias is still not fully understood, especially in nanostructures with shape anisotropy. This article provides an overview of recent experimental findings and theoretical models of exchange bias in nanostructures from various materials.
Article
Physics, Applied
Artem Talantsev, Maxim Bakhmetiev, Roman Morgunov
Summary: The magnetization reversal behavior in NiFe/IrMn exchange-biased thin films was investigated under thermal cycling, and the thermal hysteresis of magnetization and polarity changes were observed. This effect occurs when the thermally induced variations in exchange bias exceed the variations in coercivity.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Fateme Izadi, Reza Sepehrinia
Summary: We investigate the competition between ferromagnetic and spin glass phases in a system of coupled infinite-range Ising and Sherrington-Kirkpatrick models. By considering magnetization and Edwards-Anderson order parameters, we obtain the replica-symmetric solution for the free energy of the system and identify different phases as well as the dominant phase for varying coupling strengths. Interestingly, we find that although both subsystems exhibit different order parameters, they are in the same phase. The boundary between ferromagnetic and spin glass phases becomes qualitatively different as the coupling between subsystems changes, leading to a reentrant transition between these phases at intermediate coupling values accompanied by a tricritical point.
Article
Chemistry, Multidisciplinary
Bin Fang, Luis Sanchez-Tejerina San Jose, Aitian Chen, Yan Li, Dongxing Zheng, Yinchang Ma, Hanin Algaidi, Kai Liu, Giovanni Finocchio, Xixiang Zhang
Summary: This research demonstrates the feasibility of achieving perpendicular EB reversal in antiferromagnetic materials and ferromagnetic multilayers, providing a direction for introducing new functionality in spintronic devices.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Chemistry, Physical
Yi Li, Chao Sun, Kai Liu, Tong Xu, Binbin He
Summary: This paper investigates the use of the magnetic hysteresis loop technique to nondestructively evaluate microstructural degradation in heat-resistant martensitic (HRM) steels. The results show that both coercivity and hardness decrease with thermal aging duration, and there are good linear relations between coercivity, hardness, and microstructure parameters, suggesting the possibility of using magnetic technologies for the nondestructive evaluation of microstructure degradation.
Article
Materials Science, Multidisciplinary
Ravinder Kumar, S. N. Sarangi, D. Samal, Z. Hossain
Summary: Evidence of unprecedented room temperature positive exchange bias and hysteresis loop inversion has been found in monolithic Y3Fe5O12 films grown epitaxially on a (111)-oriented Gd3Fe5O12 crystal. The growth-induced interfacial layer coupling leads to positive EB and in-turn loop inversion, with a large exchange shift realized at 300 K. This discovery may have significant implications for spintronics device applications.
Article
Mathematics, Applied
Faycal Ikhouane
Summary: This paper discusses the modeling of hysteresis phenomenon in science and engineering, focusing on the Duhem model based on thermodynamical considerations. By studying the model proposed by Babuska, results regarding the existence and uniqueness of global solutions and periodic solutions, as well as the explicit analytic expression of the hysteresis loop, were obtained. The findings were applied to dry friction modeling and asymmetric hysteresis loop matching.
COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION
(2021)
Article
Materials Science, Multidisciplinary
Chhatra R. Joshi, Mahendra Acharya, Gary J. Mankey, Arunava Gupta
Summary: This study investigates the effects of thickness on the room-temperature polarization-voltage (P-V) hysteresis loop, leakage current, and average domain size of multiferroic BiFeO3 (BFO) films. The results demonstrate that BFO films indeed follow the Ishibashi-Orihara (I-O) model and the Kay-Dunn scaling law at room temperature. The dimensionality of the observed domains using piezoresponse force microscopy imaging is consistent with the results from the I-O model and Kittel's law. These findings provide valuable insights into the fundamental properties that govern the switching kinetics of BFO and their relevance for next-generation logic and memory devices operating at a wide range of frequencies.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
Ruijie Zhao, Weifeng Xu, Yanfei Wu, Xinjie Liu, Zeyu Zhang, Mengyuan Zhu, Liyuan Zhang, Jianxin Shen, Shipeng Shen, He Huang, Jingyan Zhang, Xinqi Zheng, Shouguo Wang
Summary: In this study, we investigated the self-modulated magnetic properties of FGT nanoflakes in an ambient environment and observed the unique double square-shaped hysteresis loops. We proposed a phenomenological model to explain this phenomenon and pointed out the potential applications of the double square-shaped hysteresis loops in information storage or sensing.
ACS APPLIED NANO MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
P. P. Shen, Y. T. Wang, B. A. Sun
Summary: The phenomenon of completely inverted hysteresis loop with negative remanence and positive coercivity has been observed in soft-magnetic nanocrystalline Fe73.5Cu1Nb3Si13.5B9 alloy and amorphous Fe73.5Cu1Nb3Si13.5B9 alloy at room temperature. It was found that the net coercivities of the nanocrystalline Fe73.5Cu1Nb3Si13.5B9 alloy and standard Pd sample are almost equal for different scanning field ranges, indicating that the phenomenon is caused by the remanence of superconducting magnet rather than structural inhomogeneity effects. Special care should be taken during the measurement of hysteresis loops using MPMS 3, especially for materials with small coercivity.
FRONTIERS IN MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Tong-lun Wang, Wei Wang, Hai-ling Miao, Hao-jia Wu, Bo-chen Li
Summary: In this paper, a new method of particle swarm optimization combined with Monte Carlo simulation (PSO-MC) is proposed to investigate the magnetic properties of the perovskite LaFeO3 structure described by Ising model. The exchange coupling is calculated using particle swarm optimization algorithm, and the effects of crystal field and external magnetic field on magnetization, magnetic susceptibility, entropy, phase transition temperature and internal energy of perovskite LaFeO3 are simulated using Monte Carlo method. The effects of crystal field and temperature on hysteresis loops of LaFeO3 are also studied, and the changes of coercivity and remanence under different parameters are obtained. The research results are compared with relevant theoretical and experimental results as well.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2023)
Article
Physics, Applied
Necda Cam, Umit Akinci
Summary: This study examines the dynamic hysteresis characteristics and phase transition behavior of permalloy nanodisks with different shapes and reveals the influence of shape on the dynamic behavior.
JOURNAL OF SUPERCONDUCTIVITY AND NOVEL MAGNETISM
(2023)
Article
Engineering, Electrical & Electronic
Wei Liu, Hui Yang, Heyun Lin, Xiping Liu
Summary: This study investigates the inherent relationship between the properties of low-coercive-force permanent magnets (PMs) and the electromagnetic characteristics of variable flux memory machines (VFMM) using a combined solution integrated with magnetic equivalent circuit (MEC) and graphical methods. The study models and analyzes the magnetization properties using simplified mathematical models, and qualitatively analyzes the characteristics of VFMM using a newly developed coupled approach.
IEEE TRANSACTIONS ON MAGNETICS
(2022)
Article
Chemistry, Physical
Eduard Monaico, Vadim Morari, Maksim Kutuzau, Veaceslav V. Ursaki, Kornelius Nielsch, Ion M. Tiginyanu
Summary: Uniform nanogranular NiFe layers with different Ni contents were fabricated through electroplating on planar substrates and arrays of nanowires. The magnetic properties of these layers were analyzed to evaluate their potential applications.
Article
Materials Science, Multidisciplinary
Ruijun Li, Fan Zhang, Yong Hu
Summary: The study on the temperature dependence of exchange bias field and coercivity is crucial for solving the writing/reading dilemma in magnetic recording. Based on recent experimental findings, a complete switch between the exchange bias field and coercivity with temperature is proposed. The performance, characterized by average switching temperature (TS) and switching temperature width (ATW), is controlled by antiferromagnetic anisotropy (KAF) and exchange coupling (JAF) constants.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2022)
Article
Materials Science, Multidisciplinary
A. Ehrmann, T. Blachowicz
Summary: Asymmetric hysteresis loops can be observed in exchange-bias systems and in purely ferromagnetic samples due to minor loops or thermal effects. Micromagnetic simulations of a nanoparticle structure reveal distinctly asymmetric and horizontally shifted hysteresis loops.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
T. Blachowicz, P. Steblinski, J. Grzybowski, A. Ehrmann
Summary: Magnetic nanofibers can be used for data transport and storage, and their domain walls can be utilized for semi-deterministic logic operations in bent nanofibers. The bending radius has an influence on the nucleation and propagation of the domain walls.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Green & Sustainable Science & Technology
Fabian Schoden, Joscha Detzmeier, Anna Katharina Schnatmann, Tomasz Blachowicz, Eva Schwenzfeier-Hellkamp
Summary: This article discusses the urgent situation of resource crisis and the importance of renewable energy technologies. It mentions dye-sensitized solar cells as an emerging technology that can serve as an environmentally friendly and renewable energy solution. The research found that by remanufacturing old DSSCs, their lifespan can be extended and they can be rebuilt multiple times.
Proceedings Paper
Polymer Science
Tomasz Blachowicz, Jacek Grzybowski, Andrea Ehrmann
Summary: This paper investigates the distribution of magnetic nanoparticles in polymeric or other nonmagnetic matrices, and quantifies their influence on the magnetic properties of the composite materials through micromagnetic simulations.
MACROMOLECULAR SYMPOSIA
(2022)
Article
Polymer Science
Jan Lukas Storck, Guido Ehrmann, Uwe Gueth, Jana Uthoff, Sarah Vanessa Homburg, Tomasz Blachowicz, Andrea Ehrmann
Summary: While FDM and other inexpensive 3D printing methods are widely used, their application is limited due to mechanical and thermal constraints. The study found that filled PLA filaments are the most suitable material for high-temperature conditions.
Article
Materials Science, Multidisciplinary
Pawel Steblinski, Tomasz Blachowicz, Andrea Ehrmann
Summary: This article presents micro-magnetic simulations to analyze the energy density of nano-scaled iron spheres. The effects of different coatings and thicknesses on energy uniformity, as well as the relationship between droplet size and magnetization distribution, were investigated. The study reveals that oxide-coated spheres can be placed closer together in comparison to non-coated spheres.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Review
Polymer Science
Guido Ehrmann, Tomasz Blachowicz, Andrea Ehrmann
Summary: This article provides an overview of magnetic composites 3D-printed using different techniques and their potential applications. By embedding nanoparticles in the printing material, additional functionalities can be added to the objects. The influence of printing parameters on the magnetic and mechanical properties of these polymer/magnetic composites is also discussed.
Review
Green & Sustainable Science & Technology
Fabian Schoden, Anna Katharina Schnatmann, Tomasz Blachowicz, Hildegard Manz-Schumacher, Eva Schwenzfeier-Hellkamp
Summary: In a world where resources are in high demand and climate crisis is worsening, researching and implementing sustainable and regenerative products and processes becomes crucial. Dye-sensitized solar cells (DSSCs) are a promising technology that can be manufactured with low energy input and non-toxic components, while also being recyclable, repairable and remanufacturable. This publication explores appropriate design principles and business models for DSSC technology, with the key result being a performance-based business model that integrates DSSCs into the customer's building and provides green energy as a service.
Article
Multidisciplinary Sciences
Tomasz Blachowicz, Pawel Steblinski, Andrea Ehrmann
Summary: Magnetic nanofibers with varying lengths, cross-sections, and bending radii have unique magnetic properties and are intensively studied in simulations and experiments. They have potential applications in data storage, data transport, and spintronics devices. This study focuses on the influence of a constricted area with a rotating magnetic field on the magnetization dynamics of bent or straight magnetic nanofibers, revealing the strong impact of the area, nanofiber curvature, and Dzyaloshinskii-Moriya interaction.
Review
Materials Science, Multidisciplinary
Tomasz Blachowicz, Guido Ehrmann, Andrea Ehrmann
Summary: Additive manufacturing, or 3D printing, is a versatile technology that enables the creation of objects using various polymers, metals, and other materials in diverse shapes and sizes. By using corresponding feedstock, special physical or chemical properties can be achieved. Polymer composites with conductive properties are of particular interest in 3D printing, and this article provides an overview of recent developments in this area. It discusses the conductivity ranges, potential applications, additive manufacturing methods, and measurement techniques for these composites. The article also summarizes the latest reports on 3D printing of polymer composites with different conductive fillers and highlights the applications found in the literature.
MACROMOLECULAR MATERIALS AND ENGINEERING
(2023)
Review
Biochemistry & Molecular Biology
Tomasz Blachowicz, Andrea Ehrmann
Summary: Electrospun nanofiber mats are commonly used in biotechnology or filtration due to their high specific surface area and small pore sizes. While they are typically white, their optical properties can be modified and become highly important in various applications such as sensing devices or solar cells.
Review
Materials Science, Multidisciplinary
Tomasz Blachowicz, Dariusz Wojcik, Maciej Surma, Miroslaw Magnuski, Guido Ehrmann, Andrea Ehrmann
Summary: Shielding of instruments and humans from electromagnetic interference (EMI) has become increasingly important. Textile fabrics with bendable, drapable, and stretchable EMI shielding properties are ideal for this purpose. However, conductivity and magnetic properties need to be added through conductive yarn, coatings, or fibers. Recent research has focused on MXenes due to their high conductivity and EMI shielding effectiveness, while other conductive and magnetic coatings and fibers are still promising for EMI shielding textile fabrics.
Article
Polymer Science
Al Mamun, Francisco Jose Garcia-Mateos, Lilia Sabantina, Michaela Kloecker, Elise Diestelhorst, Ramiro Ruiz-Rosas, Juana Maria Rosas, Jose Rodriguez-Mirasol, Tomasz Blachowicz, Tomas Cordero
Summary: In this study, electrospun carbon fiber electrodes were prepared for use as catalysts in the oxygen reduction reaction. The results showed that these catalysts exhibited good activity and selectivity.
Review
Materials Science, Multidisciplinary
Tomasz Blachowicz, Andreas Huetten, Andrea Ehrmann
Summary: This paper reviews recent advances in nanofiber mats for electromagnetic interference (EMI) shielding, focusing on their production, physical properties, and typical characterization techniques.
Article
Biotechnology & Applied Microbiology
Guido Ehrmann, Tomasz Blachowicz, Sarah Vanessa Homburg, Andrea Ehrmann
Summary: This review provides an overview of recent studies on the measurement of biosignals using single circuit boards, highlighting the new possibilities offered by devices like Arduino and Raspberry Pi in the mobile long-term acquisition of biosignals. The focus of the review is on the electronics, rather than textile electrodes.
BIOENGINEERING-BASEL
(2022)