Article
Chemistry, Physical
Yuhui Wang, Ying Zheng, Ziyi Zhong, Zijun Wang, Yongfeng Liang, Pingping Wu
Summary: The magnetic properties of a core-shell type exchange coupled composite structure were studied using micromagnetic simulation. Switching loops with magnetic domain structure evolution were demonstrated and a switching type diagram was constructed. The effects of switching type and composite structure on coercivity and remanent magnetization were predicted and discussed. The core-shell type FePt/Fe composite structure film was found to have a significant advantage in designing high-density storage devices at the nanoscale.
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)
Article
Materials Science, Multidisciplinary
Zijun Wang, Ying Zheng, Wangqiang He, Xingqiao Ma, Pingping Wu
Summary: After twenty years of studying the exchange spring effect, it has been found to have strong potential for application in the perpendicular record process. The exchange coupled patterned media offer a new way to increase data storage. The in-plane and out-of-plane switching processes were analyzed to enhance magnetic device design, with details like magnetic domain wall movement and hysteresis loops discussed.
JOURNAL OF MAGNETICS
(2021)
Article
Chemistry, Analytical
Pirat Khunkitti, Naruemon Wannawong, Chavakon Jongjaihan, Apirat Siritaratiwat, Anan Kruesubthaworn, Arkom Kaewrawang
Summary: This study introduces exchange-coupled composite bit-patterned media (ECC-BPM) combined with microwave-assisted magnetic recording (MAMR) to enhance the writeability of magnetic media at a recording density of 4 Tb/in^2. By evaluating the suitable microwave field frequency and exchange coupling values between magnetic dots in the proposed media, significant reductions in switching field were achieved compared to conventional media, further decreased by utilizing MAMR technology.
Article
Physics, Multidisciplinary
Wei Chen, Jincai Chen, Zongsong Gan, Yaxiong Ma, Ke Luo, Zhenxing Huang, Yang He, Ping Lu
Summary: The semi-circle resonator system proposed as the light delivery system for HAMR can provide a stable enhanced optical field to excite the localized surface plasmon of NFT without complex focusing lenses or external controls. Combined with bit-patterned media, the performance can be improved several times than the thin-film structure.
Article
Chemistry, Multidisciplinary
Maggie E. Jewett, Harrison L. Hiraki, Michal Wojasinski, Zenghao Zhang, Susan S. Xi, Amanda S. Bluem, Eashan S. Prabhu, William Y. Wang, Abdon Pena-Francesch, Brendon M. Baker
Summary: A novel method of rapidly creating organized capillary networks in metabolically demanding engineered tissue constructs was introduced through magnetizing microfiber lattices and seeding them with endothelial cells (ECs). The capillary templating lattice was then selectively degraded by a bacterial lipase, resulting in the formation of highly vascularized tissues at capillary length-scales.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Thien An Nguyen, Jaejin Lee
Summary: Bit-patterned media recording (BPMR) is a promising technology for increasing the areal density (AD) of magnetic data storage systems. In this study, the maximum a posteriori (MAP) algorithm is proposed to improve the serial detection method and address the issues of 2D interference and track mis-registration (TMR) in BPMR.
APPLIED SCIENCES-BASEL
(2022)
Article
Engineering, Electrical & Electronic
Seongkwon Jeong, Jaejin Lee
Summary: In this study, a bit-flipping scheme using the K-means algorithm for bit-patterned media recording (BPMR) system is proposed to increase the areal density of hard disk drives. The scheme reduces the distance between islands storing 1 bit and utilizes neighboring information to improve performance.
IEEE TRANSACTIONS ON MAGNETICS
(2022)
Article
Nanoscience & Nanotechnology
S. Sokjabok, M. Mattayakan, C. Buajong, S. Koonkarnkhai, P. Kovintavewat, C. Warisarn
Summary: The reduction in track width of ultra-high density magnetic recording leads to an increase in areal density, but also brings about severe inter-symbol interference and inter-track interference. To address these issues, a single-reader/two-track reading technique and constrained coding schemes are proposed, showing superior performance in mitigating ISI and ITI effects compared to conventional systems.
Article
Chemistry, Multidisciplinary
Seong Won Kim, Sangsik Park, Siyoung Lee, Daegun Kim, Giwon Lee, Jonghyun Son, Kilwon Cho
Summary: Researchers have successfully developed a stretchable high-performance organic semiconductor thin film by patterning and pinning a polymer semiconductor solution on an elastomeric substrate. This thin film exhibits superior stretchability and charge transport performance, making it suitable for applications in soft electronics.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Seongkwon Jeong, Jaejin Lee
Summary: This study proposes a modulation decoding method based on the K-means algorithm to improve decoding capabilities in bit-patterned media recording systems. Increasing the areal density makes it more difficult to detect data due to the influence of intersymbol interference (ISI) and intertrack interference (ITI), but modulation coding can prevent severe ISI and ITI caused by specific data patterns.
APPLIED SCIENCES-BASEL
(2022)
Article
Chemistry, Multidisciplinary
Gyuyeol Kong, Minchae Jung
Summary: This paper proposes a tabu search aided multi-track detection scheme for bit patterned magnetic recording. The proposed scheme adopts a simplified multi-track detector with a two-dimensional generalized partial response target, uses a priori information, and employs a reliability test and a tabu search detector. The proposed scheme processes signals in three stages, and achieves better performance compared to conventional schemes.
APPLIED SCIENCES-BASEL
(2022)
Article
Chemistry, Multidisciplinary
Seongkwon Jeong, Jaejin Lee
Summary: This study investigates the electronic structure and magnetic properties of potential two-dimensional material MnPS3 using density functional theory. The results reveal its semiconductor nature and antiferromagnetic properties, providing a theoretical basis for its applications in electronic and magnetic devices.
APPLIED SCIENCES-BASEL
(2022)
Article
Engineering, Electrical & Electronic
Hikaru Yamane, Simon John Greaves, Yoichiro Tanaka
Summary: Modeling heat-assisted magnetic recording on bit patterned media dots with two magnetic structures showed that storing two bits of information in each dot is possible. The areal density capability of the dual structure media was calculated to exceed 7 Tbit/in(2) despite dot position distributions and magnetostatic fields from surrounding dots.
IEEE TRANSACTIONS ON MAGNETICS
(2021)
Article
Chemistry, Multidisciplinary
Thien An Nguyen, Jaejin Lee
Summary: Bit-patterned media recording (BPMR) is proposed as a candidate solution for addressing superparamagnetism issues in magnetic data storage. This study focuses on reducing the distance between magnetic islands in BPMR to increase the areal density, while also addressing the increased two-dimensional interference. A new estimator based on the 2D Viterbi algorithm (VA) with reduced states is proposed to predict interference from neighboring tracks. Simulation results demonstrate the superiority of this model compared to previous models.
APPLIED SCIENCES-BASEL
(2022)
Article
Multidisciplinary Sciences
Horst Rottke, Robin Y. Engel, Daniel Schick, Jan O. Schunck, Piter S. Miedema, Martin C. Borchert, Marion Kuhlmann, Nagitha Ekanayake, Siarhei Dziarzhytski, Gunter Brenner, Ulrich Eichmann, Clemens von Korff Schmising, Martin Beye, Stefan Eisebitt
Summary: Extending nonlinear spectroscopic techniques into the x-ray domain allows for unique insights into photoexcited charge dynamics. We have observed a third-order nonlinear process in lithium fluoride (LiF) and found that resonant four-wave mixing (FWM) can be used as a sensitive probe for charge localization.
Article
Instruments & Instrumentation
Nanna Zhou Hagstrom, Michael Schneider, Nico Kerber, Alexander Yaroslavtsev, Erick Burgos Parra, Marijan Beg, Martin Lang, Christian M. Gunther, Boris Seng, Fabian Kammerbauer, Horia Popescu, Matteo Pancaldi, Kumar Neeraj, Debanjan Polley, Rahul Jangid, Stjepan B. Hrkac, Sheena K. K. Patel, Sergei Ovcharenko, Diego Turenne, Dmitriy Ksenzov, Christine Boeglin, Marina Baidakova, Clemens von Korff Schmising, Martin Borchert, Boris Vodungbo, Kai Chen, Chen Luo, Florin Radu, Leonard Mueller, Miriam Martinez Florez, Andre Philippi-Kobs, Matthias Riepp, Wojciech Roseker, Gerhard Gruebel, Robert Carley, Justine Schlappa, Benjamin E. Van Kuiken, Rafael Gort, Laurent Mercadier, Naman Agarwal, Loic Le Guyader, Giuseppe Mercurio, Martin Teichmann, Jan Torben Delitz, Alexander Reich, Carsten Broers, David Hickin, Carsten Deiter, James Moore, Dimitrios Rompotis, Jinxiong Wang, Daniel Kane, Sandhya Venkatesan, Joachim Meier, Florent Pallas, Tomasz Jezynski, Maximilian Lederer, Djelloul Boukhelef, Janusz Szuba, Krzysztof Wrona, Steffen Hauf, Jun Zhu, Martin Bergemann, Ebad Kamil, Thomas Kluyver, Robert Rosca, Michal Spirzewski, Markus Kuster, Monica Turcato, David Lomidze, Andrey Samartsev, Jan Engelke, Matteo Porro, Stefano Maffessanti, Karsten Hansen, Florian Erdinger, Peter Fischer, Carlo Fiorini, Andrea Castoldi, Massimo Manghisoni, Cornelia Beatrix Wunderer, Eric E. Fullerton, Oleg G. Shpyrko, Christian Gutt, Cecilia Sanchez-Hanke, Hermann A. Durr, Ezio Iacocca, Hans T. Nembach, Mark W. Keller, Justin M. Shaw, Thomas J. Silva, Roopali Kukreja, Hans Fangohr, Stefan Eisebitt, Mathias Klaui, Nicolas Jaouen, Andreas Scherz, Stefano Bonetti, Emmanuelle Jal
Summary: The advent of X-ray free-electron lasers (XFELs) has revolutionized fundamental science, providing researchers with unprecedented brightness, coherence, and pulse duration. This paper presents the results from the first megahertz-repetition-rate X-ray scattering experiments at the Spectroscopy and Coherent Scattering (SCS) instrument of the European XFEL. The experimental capabilities offered by the SCS instrument, operating at a megahertz repetition rate and using a novel DSSC 2D imaging detector, are illustrated.
JOURNAL OF SYNCHROTRON RADIATION
(2022)
Article
Multidisciplinary Sciences
Christopher Klose, Felix Buettner, Wen Hu, Claudio Mazzoli, Kai Litzius, Riccardo Battistelli, Ivan Lemesh, Jason M. Bartell, Mantao Huang, Christian M. Guenther, Michael Schneider, Andi Barbour, Stuart B. Wilkins, Geoffrey S. D. Beach, Stefan Eisebitt, Bastian Pfau
Summary: Nanoscale magnetic fluctuations are observed beyond conventional resolution limits using coherent correlation imaging, allowing for the study of previously inaccessible magnetic phenomena. The method utilizes Fourier space analysis and an iterative hierarchical clustering algorithm to achieve high spatial and temporal resolution.
Correction
Physics, Multidisciplinary
Allan S. Johnson, Daniel Perez-Salinas, Khalid M. Siddiqui, Sungwon Kim, Sungwook Choi, Klara Volckaert, Paulina E. Majchrzak, Soren Ulstrup, Naman Agarwal, Kent Hallman, Richard F. Haglund, Christian M. Guenther, Bastian Pfau, Stefan Eisebitt, Dirk Backes, Francesco Maccherozzi, Ann Fitzpatrick, Sarnjeet S. Dhesi, Pierluigi Gargiani, Manuel Valvidares, Nongnuch Artrith, Frank de Groot, Hyeongi Choi, Dogeun Jang, Abhishek Katoch, Soonnam Kwon, Sang Han Park, Hyunjung Kim, Simon E. Wall
Article
Physics, Multidisciplinary
Allan S. Johnson, Daniel Perez-Salinas, Khalid M. Siddiqui, Sungwon Kim, Sungwook Choi, Klara Volckaert, Paulina E. Majchrzak, Soren Ulstrup, Naman Agarwal, Kent Hallman, Richard F. Haglund, Christian M. Guenther, Bastian Pfau, Stefan Eisebitt, Dirk Backes, Francesco Maccherozzi, Ann Fitzpatrick, Sarnjeet S. Dhesi, Pierluigi Gargiani, Manuel Valvidares, Nongnuch Artrith, Frank de Groot, Hyeongi Choi, Dogeun Jang, Abhishek Katoch, Soonnam Kwon, Sang Han Park, Hyunjung Kim, Simon E. Wall
Summary: Using time- and spectrally resolved coherent X-ray imaging, the researchers track the prototypical light-induced insulator-to-metal phase transition in vanadium dioxide on the nanoscale with femtosecond time resolution. They observe that the early-time dynamics are independent of the initial spatial heterogeneity and show a 200 fs switch to the metallic phase. Heterogeneous response emerges only after hundreds of picoseconds.
Article
Instruments & Instrumentation
J. Correa, M. Mehrjoo, R. Battistelli, F. Lehmkuehler, A. Marras, C. B. Wunderer, T. Hirono, V Felk, F. Krivan, S. Lange, I Shevyakov, V. Vardanyan, M. Zimmer, M. Hoesch, K. Bagschik, N. Guerrini, B. Marsh, I Sedgwick, G. Cautero, L. Stebel, D. Giuressi, R. H. Menk, A. Greer, T. Nicholls, W. Nichols, U. Pedersen, P. Shikhaliev, N. Tartoni, H. J. Hyun, S. H. Kim, S. Y. Park, K. S. Kim, F. Orsini, F. J. Iguaz, F. Buettner, B. Pfau, E. Ploenjes, K. Kharitonov, M. Ruiz-Lopez, R. Pan, S. Gang, B. Keitel, H. Graafsma
Summary: The PERCIVAL detector is a CMOS imager specifically designed for the soft X-ray regime. It has been used in various user experiments, such as ptychography, holographic imaging, and X-ray photon correlation spectroscopy. The detector has shown remarkable performance in terms of spatial resolution and frame rate, making it an attractive option for soft X-ray science.
JOURNAL OF SYNCHROTRON RADIATION
(2023)
Article
Optics
Martin Borchert, Dieter Engel, Clemens Von Korff Schmising, Bastian Pfau, Stefan Eisebitt, Daniel Schick
Summary: Time-resolved x-ray magnetic circular dichroism (XMCD) provides a unique spectroscopic technique to study spin and charge dynamics in multi-elemental magnetic materials. However, its application in the soft-x-ray range has been limited. Our development of a laser-driven plasma source combined with a magnetic thin-film polarizer enables XMCD spectroscopy at the Fe L edges in a laser laboratory for the first time. This approach can be extended to other absorption edges and allows for ultrafast magnetization studies with temporal resolution of < 10 ps.
Article
Chemistry, Physical
Kathinka Gerlinger, Bastian Pfau, Martin Hennecke, Lisa-Marie Kern, Ingo Will, Tino Noll, Markus Weigand, Joachim Graefe, Nick Traeger, Michael Schneider, Christian M. Guenther, Dieter Engel, Gisela Schuetz, Stefan Eisebitt
Summary: In this study, we demonstrate time-resolved scanning X-ray microscopy measurements using a tailored infrared pump laser at a scanning transmission X-ray microscope. By controlling the heat load on the sample, we can conduct destruction-free measurements at a high repetition rate. Our work provides new opportunities to study photo-induced dynamics on the nanometer scale, with access to picosecond to nanosecond time scales, which is of technological relevance, especially in the field of magnetism.
STRUCTURAL DYNAMICS-US
(2023)
Article
Instruments & Instrumentation
Martin Borchert, Julia Braenzel, Richard Gnewkow, Leonid Lunin, Themistoklis Sidiropoulos, Johannes Tuemmler, Ingo Will, Tino Noll, Oliver Reichel, Dirk Rohloff, Alexei Erko, Thomas Krist, Clemens von Korff Schmising, Bastian Pfau, Stefan Eisebitt, Holger Stiel, Daniel Schick
Summary: We present a laser-driven soft-x-ray plasma source with short pulse duration and wide spectral range. This source is used in two laboratory-scale beamlines for time-resolved magnetic resonant scattering, spectroscopy, and NEXAFS spectroscopy. Dedicated reflection zone plates are utilized as optical elements to capture, disperse, and focus the soft x rays, achieving high resolving powers and efficient data acquisition. Our setup enables soft-x-ray experiments that were not previously possible on a laboratory scale, making it a viable alternative to large-scale facilities.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2023)
Article
Physics, Multidisciplinary
Clemens von Korff Schmising, Somnath Jana, Kelvin Yao, Martin Hennecke, Philippe Scheid, Sangeeta Sharma, Michel Viret, Jean-Yves Chauleau, Daniel Schick, Stefan Eisebitt
Summary: The ultrafast response of CoFeB/Pt bilayers was studied by probing element-specific, core-to-valence-band transitions using high harmonic radiation in the extreme ultraviolet spectral range. Through magnetic scattering simulations and analysis of the energy- and time-dependent magnetic asymmetries, the element-specific response was accurately disentangled. It was found that the induced moment of Pt in the bilayer has a considerably smaller demagnetization time constant and much larger demagnetization amplitudes compared to the intrinsic moment of CoFeB.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Materials Science, Multidisciplinary
Christopher Klose, Felix Buettner, Wen Hu, Claudio Mazzoli, Geoffrey S. D. Beach, Stefan Eisebitt, Bastian Pfau
Summary: This paper proposes a method to reconstruct magnetic scattering signal using heterodyne scattering, which directly represents the magnetization texture. It solves some problems in traditional methods and eliminates the issue of artificial decay of correlation functions through the implementation method.
Article
Physics, Multidisciplinary
Martin Hennecke, Daniel Schick, Themistoklis Sidiropoulos, Felix Willems, Anke Heilmann, Martin Bock, Lutz Ehrentraut, Dieter Engel, Piet Hessing, Bastian Pfau, Martin Schmidbauer, Andreas Furchner, Matthias Schnuerer, Clemens von Korff Schmising, Stefan Eisebitt
Summary: We investigated the femtosecond laser-induced spin dynamics in nanostructured magnetic materials using time- and angle-resolved transverse magneto-optical Kerr effect spectroscopy in the soft x-ray range. Through polarization-dependent magnetic scattering simulations, we determined the spatiotemporal and element-specific evolution of spin dynamics and understand the contributions from nonequilibrium electron transport and nanoscale heat diffusion.
PHYSICAL REVIEW RESEARCH
(2022)
