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
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
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
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, 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
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
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
Computer Science, Information Systems
Thien An Nguyen, Jaejin Lee
Summary: This article examines a new distribution of bit-patterned media recording called staggered BPMR. By dividing the interference into three parts and using three one-dimensional detectors, the proposed model improves the detection performance of the main data. Simulation results demonstrate that this model outperforms previous studies.
Article
Chemistry, Multidisciplinary
Thien An Nguyen, Jaejin Lee
Summary: Ultra-high density data storage, specifically using bit-pattern media recording (BPMR), is crucial due to the increasing volumes of data. A neural network model for noise prediction has been proposed to improve the performance of serial detection, resulting in approximately 1 dB gain in bit error rate (BER) compared to the model with a feedback line.
APPLIED SCIENCES-BASEL
(2021)
Article
Chemistry, Multidisciplinary
Thien An Nguyen, Jaejin Lee
Summary: This study investigates the impact of varying the form of the GPR target in bit-patterned media recording systems, and proposes a multilayered 2D GPR target and a detection method for improving interference estimation accuracy.
APPLIED SCIENCES-BASEL
(2022)
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
Engineering, Electrical & Electronic
Seongkwon Jeong, Jaejin Lee
Summary: The study proposes using extrinsic information obtained from an MLP equalizer to improve the detection performance of BPMR in PRML detector, showing better performance compared to both MLP equalizer and conventional PRML alone. The proposed detector also provides improved performance when track misregistration occurs.
IEEE TRANSACTIONS ON MAGNETICS
(2021)
Article
Multidisciplinary Sciences
Tianbo Xue
Summary: This paper introduces a probabilistic channel model with correlated insertion and deletion errors for bit-patterned media recording systems and investigates the error performance and decoding complexity of a concatenated LDPC-marker code over the CID channel. By modifying the decoding algorithm and considering the data dependence, the LDPC-marker code shows improved performance and reduced decoding complexity on average.
Article
Engineering, Electrical & Electronic
Pierre-Olivier Jubert, Fenghua Zong, Michael K. Grobis
IEEE TRANSACTIONS ON MAGNETICS
(2017)
Article
Polymer Science
Ricardo Ruiz, Lei Wan, Rene Lopez, Thomas R. Albrecht
Article
Polymer Science
Jun Chen, Andrea Fasoli, Julia D. Cushen, Lei Wang, Ricardo Ruiz
Article
Materials Science, Multidisciplinary
K. Hono, Y. K. Takahashi, Ganping Ju, Jan-Ulrich Thiele, Antony Ajan, XiaoMin Yang, Ricardo Ruiz, Lei Wan
Article
Nanoscience & Nanotechnology
Lei Wan, Ricardo Ruiz
ACS APPLIED MATERIALS & INTERFACES
(2019)
Article
Physics, Applied
K. Aryana, J. T. Gaskins, J. Nag, J. C. Read, D. H. Olson, M. K. Grobis, P. E. Hopkins
APPLIED PHYSICS LETTERS
(2020)
Article
Materials Science, Multidisciplinary
Cherie R. Kagan, Taeghwan Hyeon, Dae-Hyeong Kim, Ricardo Ruiz, Maryann C. Tung, H-S Philip Wong
Article
Multidisciplinary Sciences
Kiumars Aryana, John T. Gaskins, Joyeeta Nag, Derek A. Stewart, Zhaoqiang Bai, Saikat Mukhopadhyay, John C. Read, David H. Olson, Eric R. Hoglund, James M. Howe, Ashutosh Giri, Michael K. Grobis, Patrick E. Hopkins
Summary: Phase change memory (PCM) is a rapidly growing technology that offers advancements in storage-class memories and enables in-memory data processing. By manipulating the interfacial thermal resistance between the phase change unit and the electrodes, reductions in effective thermal conductivity and reset current can be achieved, leading to opportunities for power reduction in PCMs.
NATURE COMMUNICATIONS
(2021)
Article
Multidisciplinary Sciences
Kiumars Aryana, Derek A. Stewart, John T. Gaskins, Joyeeta Nag, John C. Read, David H. Olson, Michael K. Grobis, Patrick E. Hopkins
Summary: By systematically tailoring the cross-linking network among the atoms, the authors successfully suppressed the thermal transport in amorphous chalcogenide alloy SiTe, reducing the thermal conductivity by nearly an order of magnitude. The experimental results demonstrate that the ultralow thermal conductivity is attributed to the suppressed contribution of extended modes of vibration, particularly propagons and diffusons. This mechanism could potentially lead to significant advancements in thermal management for data storage and energy scavenging applications.
NATURE COMMUNICATIONS
(2021)
Article
Nanoscience & Nanotechnology
Boyce S. Chang, Whitney S. Loo, Beihang Yu, Scott Dhuey, Lei Wan, Paul F. Nealey, Ricardo Ruiz
Summary: We report a method for directed self-assembly of block copolymers using polymer inks that interpenetrate with existing polymer brushes. By selecting appropriate polymer inks, self-registered chemical contrast patterns can be generated at the same frequency as block copolymer domains. This method allows for a higher tolerance to dimensional and chemical imperfections in the guiding patterns.
ACS APPLIED MATERIALS & INTERFACES
(2020)
Article
Chemistry, Physical
Hongbo Feng, Moshe Dolejsi, Ning Zhu, Soonmin Yim, Whitney Loo, Peiyuan Ma, Chun Zhou, Gordon S. W. Craig, Wen Chen, Lei Wan, Ricardo Ruiz, Juan J. de Pablo, Stuart J. Rowan, Paul F. Nealey
Summary: This paper presents a high-throughput synthesis and characterization platform for the discovery and optimization of block copolymers (BCPs) for lithographic patterning. By synthesizing a library of BCPs covering a large parameter space, researchers are able to identify BCP chemistries that satisfy the design rules.
Article
Polymer Science
Whitney S. Loo, Hongbo Feng, Thomas J. Ferron, Ricardo Ruiz, Daniel F. Sunday, Paul F. Nealey
Summary: This study experimentally measured the extent of mixing and segregation strength of a series of lamellar A-b-(B-r-C) block copolymers. The researchers proposed using the extent of mixing to evaluate the thermodynamic parameters of block copolymers.
Article
Chemistry, Physical
He Li, Boyce S. Chang, Hyunseok Kim, Zongliang Xie, Antione Laine, Le Ma, Tianlei Xu, Chongqing Yang, Junpyo Kwon, Steve W. Shelton, Liana M. Klivansky, Virginia Altoe, Bing Gao, Adam M. Schwartzberg, Zongren Peng, Robert O. Ritchie, Ting Xu, Miquel Salmeron, Ricardo Ruiz, K. Barry Sharpless, Peng Wu, Yi Liu
Summary: Designing high-capacity polymer dielectrics that can operate efficiently under harsh electrical conditions is challenging. However, polysulfates synthesized through SuFEx catalysis were found to be high-performing dielectric polymers that can overcome these challenges. Free-standing polysulfate thin films exhibit superior insulating properties and dielectric stability at high temperatures, which can be further improved with ultrathin oxide coatings. These advancements lead to electrostatic film capacitors with high breakdown strength and discharged energy density, outperforming current state-of-the-art dielectric materials.
Proceedings Paper
Engineering, Electrical & Electronic
G. Mihajlovic, N. Smith, T. Santos, Z. Bai, M. Tran, J. Li, M. Carey, M. K. Grobis, J. A. Katine
32ND MAGNETIC RECORDING CONFERENCE (TMRC 2021)
(2021)
Article
Chemistry, Multidisciplinary
Lei Wan, Ricardo Ruiz, He Gao, Thomas R. Albrecht