Recording Media Research Articles

Effect of an agglomeration-suppressed metal island buffer layer on nanostructure of FePt-oxide granular films for heat assisted magnetic recording media

Effect of an agglomeration-suppressed metal island buffer layer on nanostructure of FePt-oxide granular films for heat assisted magnetic recording media

Recording Reflection Volume Holographic Gratings with Enhanced Performance by Two‐Stage Photopolymers Containing Bifunctional Monomers

AbstractA holographic optical waveguide (HOW) is an optimal solution for augmented reality (AR) displays, in which reflection volume holographic gratings are core optical elements. In this study, five high‐refractive‐index (≈1.6) bifunctional acrylate monomers (TPBSAs) are designed and synthesized. A series of two‐stage photopolymers are prepared using TPBSAs as writing monomers. Among them, one containing 9 wt.% TPBSA‐3 shows the best holographic recording performance with a sensitivity as high as 26.59 cm mJ−1. Using it as the recording medium, a reflection VHG can be obtained with high spatial frequency (5634 lines per mm), diffraction efficiency (97.14%), refractive index modulation (0.029), and good transparency within 400−800 nm after photobleaching. Furthermore, a HOW capable of achieving virtual and real image fusion is fabricated.

Periodically Sinusoidal Magnetic Stray Field and Improved Film Quality of CoMnP Micro-Magnet Arrays for Magnetic Encoders by Electrodeposition with the Assistance of Ultrasound

Magnetic encoders are composed of a magnetic sensor, a hard magnetic recording medium and a signal processing circuit. Electrodeposited micro-magnet arrays produced by micro-fabrication are promising recording media for enhancing encoder performance. However, two major engineering issues have yet to be resolved. One issue is an unknown relationship between the feature sizes of micro-magnet arrays and their stray field shapes, and another issue is the formation of micro-cracks due to the built-up residual stresses of thick films. In this study, we investigated the effect of feature sizes on the emanating stray field shape at various observation heights. Feature sizes include two height (i.e., film thickness) values of 78 μm and 176 μm, and both width and spacing with three values of 360 μm, 520 μm and 680 μm. Ultrasound-assisted agitation was adopted for investigating the effects of electrodepositing current densities on the film crystalline microstructures and magnetic properties. Narrowing the width of micro-magnets helps the stray field to become a sinusoidal profile. Thinner film, i.e., thickness 78 μm in this study, supports the stray field taking on a sinusoidal profile. Moreover, the spacing between the micro-magnets plays a key factor in determining the shape of the stray field. Under 37 kHz/156 W ultrasound agitation, the optimal hard magnetic properties of electrodeposited CoMnP films are residual magnetization 2329 G and coercivity 968 Oe by a current density of 10.0 mA/cm2. Ultrasound-assisted electrodeposition, along with duly designed feature size, facilitates the micro-magnet arrays having a sinusoidal stray field shape using high quality films. Furthermore, for the first time, a systematic understanding of feature-size-dependent stray field evolution and improved polarities quality has been realized for the recording media of sinusoidal magnetic encoders.

A Study on a Spatiotemporal Entity-Based Event Data Model

An event is an important medium for recording, expressing, and understanding the real world. Additionally, a data model can provide a digital and structured description method for the real world. Therefore, studying event data models is highly important for describing the real world. By analyzing the representational categories of the existing event data models, the representation of existing event models was found to have different emphases and not be sufficiently balanced, and the universality and comprehensiveness need to be improved. Therefore, based on the advantages of the ontological event model in expressing semantic information and the advantages of the object-event-based spatiotemporal data model in expressing entity multidimensional characteristics and dynamic processes, a spatiotemporal entity-based event data model and the modeling method were designed to provide model support for event organization and processing. Additionally, the Long March and its important battles were selected as case studies to validate the proposed model. The validation shows that the proposed model performs well in terms of event dynamics, hierarchical structure, and complex interrelationships.

Polarization‐Controlled Diffractions of Submicron Pillar Arrays of Azo Molecular Glass for Image Recording and Reconstruction

Recording and manipulating optical waves with functional structures are crucially important for many applications. Herein, the submicron pillar arrays of an azo molecular glass (IA‐Chol) are explored to show functional synergy of a recording medium and a diffractive optical element. The image recording is achieved through the pillar deformation along the electric‐field oscillation direction of incident light. When illuminated with a polarized beam, the reconstructed images appear in the first‐order diffraction spots of the pillar array with the tailored intensity distributions depending on the states of polarization of the recording beam and the image reconstruction beam. This approach enables several images to be recorded in the adjacent zones of the same pillar array using lights with different polarization directions, and then the images are reconstructed separately or simultaneously upon the polarization directions of the illumination light. Furthermore, the topographic features of the pillar array after the recording are replicated by replica‐molding to the surfaces of polydimethylsiloxane (PDMS) slices as negative replicas and transformed to surfaces of poly(methylmethacrylate) (PMMA) films through hot‐embossing. The PDMS and PMMA replicas are highly transparent in the visible light range and able to produce the reconstructed images with light in a wide‐wavelength extent.

Exploration of drag on the thin film of micropolar fluid flow within a permeable medium

Advances in thin film acquired many industrial applications because of their use in several products like electronic devices, magnetic recording media, LED, optical coating, etc. Additionally, thin film has an extensive role in the study of multiferroic materials and superlattices in quantum phenomena. Therefore, it is an urge to predict the importance of drag employing Darcy-Forchheimer on the thin film flow of micropolar liquid through an expanding plate embedding with a permeable medium. Moreover, the current model enriches by incorporating the impact of Soret because of the cross-diffusion process and the radiative heat. By using the appropriate transformed variables, the designed problem is distorted, and further, these sets of equations are handled numerically employing Runge-Kutta shooting technique. The computation is carried out by deploying in-house built-in function bvp4c in MATLAB. The significant operational behavior of the manipulated quantities is accessible graphically and deliberated in the discussion section. The important findings are elaborated as; the angular velocity distribution shows a greater deceleration for the increasing microrotation and the inertial drag effect. Further, the thermo-diffusion due to Soret also attenuates the concentration profile and the solutal thickness became thinner for the higher heavier species.

Structural, spectral, dielectric, and magnetic properties of Gd3+ substituted Y-type Barium hexaferrites

Co-precipitation method is used to prepare Mn2Ba2GdxFe12-xO22 (0.00, 0.05, 0.10, 0.15, 0.20, and 0.25) Y-type hexaferrites. X-ray diffraction patterns reviled that prepared samples have single phase. The lattice parameters of ‘a’ and ‘c’ increases from 5.87 Å to 5.89 Å and 43.50 Å to 43.68 Å with the incorporation of Gd3+ (Gadolinium), respectively. Samples crystallite sizes were in the 88.8–201 nm range. The spectrum of FTIR explains Fe-O vibrational bands, which signifies the formation of Y-type hexaferrites. The maximum quality factor ‘Q’ value is obtained at 2 GHz. The maximum Q value at high frequency suggests the potential uses of prepared samples for multilayered chip inductors operating at high frequencies. A reduction in the values of saturation magnetization (Ms), coercivity (Hc) as well as in remanence (Mr) were observed in 32.0–10.2 emu/g, 19.30–5.41 emu/g, and 3084.60–1071.3 Oe range respectively. The decrement in the squareness ratio was also found in the range of 0.594–0.529. The values of squareness ratios greater than 0.5 specify that the prepared materials have a sole magnetic domain. Due to the high coercivity of the prepared materials, these could be used in devices that use high frequencies and perpendicular recording mediums.

Microwave absorption properties of ytterbium substituted X-type ferrite in P-, L-, S-, and C-band

Ba1.5Sr0.5Zn2Fe28-xYbxO46 (x = 0.00, 0.07, 0.14, 0.21, and 0.28) hexaferrite were synthesized via sol-gel auto-combustion route to investigate the microwave absorption performance in different frequency bands. The structure has a single phase, and the variation in lattice parameter was observed due to Yb-content as host iron Fe3+ and substituted Yb3+ having different ionic radii. Microwave absorbing materials (MAMs) need to be lightweight, and the maximum crystallite size of prepared material is 41 nm. The physical properties vary with substitution, and the X-ray density value is higher than the bulk density, and the porosity of the prepared sample increases when the bulk density decreases. Micro-strain values are inverse to the crystallite size because Yb3+ has larger ionic radii than Fe3+. Rietveld refinement of the XRD patterns was conducted with a lower significance value. FTIR bands observed between 414 and 500 cm−1 are present due to iron-oxygen bond stretching and bending vibrations at octahedral and tetrahedral lattice sites. The cation distribution is highly responsible for the peak position of octahedral and tetrahedral sites—the dielectric constant increases with frequency because of dipole, interfacial, and electronic/atomic polarization. AC conductivity is very low, reflecting that the material can be used as a dielectric medium in the microwave frequency range's L, S, and C bands. The best MAM among all prepared materials is Ba1.5Sr0.5Zn2Fe27.72Yb0.28O46 which can be used for global positioning systems, weather radar, and satellite feeds as it has an excellent dielectric loss, remarkable tangential loss, and the reflection loss in P-, L-, S-, and C-bands. Other real-life application of all prepared materials are multi-layer chip inductor and longitudinal media recording.

Investigation of magnetocapacitance and magnetoconductivity in single-phase Y-Type hexaferrite Ba2Co2Fe12O22 nanoparticles

This research paper examines the synthesis and characterization of Y-type hexaferrite Ba2Co2Fe12O22 nanoparticles produced using the sol-gel method. The study explores their structural, magnetic, and electrical properties, confirming the successful synthesis of pure-phase hexaferrites with a hexagonal structure at an annealing temperature of 1150 °C. Morphological analysis reveals changes in nanoparticle diameter based on varying annealing temperatures. The Ba2Co2Fe12O22 nanoparticles display soft ferrimagnetism, achieving a peak saturation magnetization of 52.31 emu/g at 1150 °C, along with notable magnetocrystalline anisotropy and anisotropy field. Investigations on magnetocapacitance and magnetoconductivity under magnetic fields revealed improved performance, with high magnetocapacitance (MC%) and magnetoconductivity (MσAC%) percentages of 24 % and 21 %, respectively. This suggests the potential utility of these nanoparticles in applications such as permanent magnets, magnetic recording media, and spintronic devices.

Elucidating sequence-function relationships in a template-independent polymerase to enable novel DNA recording applications.

Harnessing DNA as a high-density storage medium for information storage and molecular recording of signals has been of increasing interest in the biotechnology field. Recently, progress in enzymatic DNA synthesis, DNA digital data storage, and DNA-based molecular recording has been made by leveraging the activity of the template-independent DNA polymerase, terminal deoxynucleotidyl transferase (TdT). TdT adds deoxyribonucleotides to the 3' end of single-stranded DNA, generating random sequences of single-stranded DNA. TdT can use several divalent cations for its enzymatic activity and exhibits shifts in deoxyribonucleotide incorporation frequencies in response to changes in its reaction environment. However, there is limited understanding of sequence-structure-function relationships regarding these properties, which in turn limits our ability to modulate TdT to further advance TdT-based tools. Most TdT literature to-date explores the activity of murine, bovine or human TdTs; studies probing TdT sequence and structure largely focus on strictly conserved residues that are functionally critical to TdT activity. Here, we explore non-conserved TdT sequence space by surveying the natural diversity of TdT. We characterize a diverse set of TdT homologs from different organisms and identify several TdT residues/regions that confer differences in TdT behavior between homologs. The observations in this study can design rules for targeted TdT libraries, in tandem with a screening assay, to modulate TdT properties. Moreover, the data can be useful in guiding further studies of potential residues of interest. Overall, we characterize TdTs that have not been previously studied in the literature, and we provide new insights into TdT sequence-function relationships.

Three-Layer Exchange Coupled Composite Media for Heat-Assisted Magnetic Recording

Three-Layer Exchange Coupled Composite Media for Heat-Assisted Magnetic Recording

Magnetic and structural enhanced characterization of Zr-Al substituted M-type barium hexaferrite

Co-precipitation method was used to fabricate Zr-Al substituted M-Type barium hexagonal ferrite with a unique composition Ba1-xZr0.5x Al0.3 Fe11.7 O19 (x = 0.0, 0.1, 0.2, 0.3, 0.4, and 0.5). The materials were characterized using Fourier Transform Infrared spectroscopy and a magnetic hysteresis loop. For each sample, the values of Ms, Hc, Mr, remanence ratios (Mr/Ms), and magneton number (nB) are determined using M-H loops. The Mr/Ms ratio of the synthesized hexaferrites particles is between 0.001017 and 0.143103, indicating a single magnetic domain. FTIR spectroscopy was used to study the inter-atomic forces and gives information about the absorption and emission spectrum for solids, liquids and gases. The results indicate that the synthesized compounds may have potential use as perpendicular magnetic recording media due to the growing trend in saturation magnetization, remanence, and coercivity.

Using Long Short-Term Memory to Estimate the 2-D Interference of Bit-Patterned Media Recording Systems

Using Long Short-Term Memory to Estimate the 2-D Interference of Bit-Patterned Media Recording Systems

Optimization of Layer Thicknesses for Dual-Layer Bit-Patterned Media Recording (BPMR) Systems

Optimization of Layer Thicknesses for Dual-Layer Bit-Patterned Media Recording (BPMR) Systems

High Refractive Index, Low Birefringence Holographic Materials via the Homopolymerization of 1,2-Dithiolanes.

High refractive index, low birefringence photopolymers were created via the radical-mediated, ring opening homopolymerization of 1,2-dithiolane functionalized monomers and were subsequently evaluated as holographic recording media. This investigation systematically characterized the reaction kinetics, thermodynamics, and volume shrinkage of the 1,2-dithiolane homopolymerization as well as the optical transparency, refractive index, birefringence, and holographic performance of multifunctional 1,2-dithiolane functionalized monomers and their resultant polymers. Real-time kinetic and thermodynamic analyses of a monofunctional 1,2-dithiolane monomer, lipoic acid methyl ester (LipOMe), indicated rapid monomer conversion, exceeding 90% in 60 s, with an overall enthalpy of reaction of 18 ± 1 kJ/mol. The ring-opening polymerization resulted in low shrinkage (10.6 ± 0.3 cm3/mol dithiolane) and a significant bulk refractive index increase (0.030 ± 0.003). The resulting photopolymers exhibited high optical transparency, minimal haze, and negligible birefringence, suggesting the potential of 1,2-homopolymers as optical materials. To further explore the specific capabilities for use as high-performance holographic recording applications, several multifunctional monomers were synthesized with the ethanedithiol lipoic acid monomer (EDT-Lip2) selected for experimentation. Holographic diffraction gratings written using this monomer achieved a peak-to-mean refractive index modulation of 0.008 with minimal haze and birefringence.

Ab Initio Studies of Mechanical, Dynamical, and Thermodynamic Properties of Fe-Pt Alloys.

The density functional theory (DFT) framework in the generalized gradient approximation (GGA) was employed to study the mechanical, dynamical, and thermodynamic properties of the ordered bimetallic Fe-Pt alloys with stoichiometric structures Fe3Pt, FePt, and FePt3. These alloys exhibit remarkable magnetic properties, high coercivity, excellent chemical stability, high magnetization, and corrosion resistance, making them potential candidates for application in high-density magnetic storage devices, magnetic recording media, and spintronic devices. The calculations of elastic constants showed that all the considered Fe-Pt alloys satisfy the Born necessary conditions for mechanical stability. Calculations on macroscopic elastic moduli showed that Fe-Pt alloys are ductile and characterized by greater resistance to deformation and volume change under external shearing forces. Furthermore, Fe-Pt alloys exhibit significant anisotropy due to variations in elastic constants and deviation of the universal anisotropy index value from zero. The equiatomic FePt showed dynamical stability, while the others showed softening of soft modes along high symmetry lines in the Brillouin zone. Moreover, from the phonon densities of states, we observed that Fe atomic vibrations are dominant at higher frequencies in Fe-rich compositions, while Pt vibrations are prevalent in Pt-rich.

Characterization of a CMOS camera based film digitization platform for gated x-ray imaging diagnostics at the National Ignition Facility.

Hardened gated x-ray detectors use photographic film as the data recording medium due to its low sensitivity to the high-yield neutron environments at the National Ignition Facility (NIF). The photographic film is digitized with a Photometric Data Systems (PDS) microdensitometer, which measures the film's optical density. The PDS scanner is able to measure a dynamic range of 0-5 OD; however, raster scanning the film is time consuming and maintenance of the instrument is challenging due to legacy technology. Since film usage at NIF is expected to continue in the foreseeable future, a digitization platform that is faster and more maintainable would benefit the NIF's current and future operations. This work presents the characterization of the digital transitions (DT) atom, a CMOS camera-based digitization platform that records film data in a single image capture very quickly and has widely available user support. The preliminary results suggest that the DT atom is able to reconstruct exposures accurately enough to be a competitive alternative to the PDS Scanner.

Anti-noise performance analysis in amplitude-modulated collinear holographic data storage using deep learning

In an amplitude-modulated collinear holographic data storage system, optical system aberration and experimental noise due to the recording medium often result in a high bit error rate (BER) and low signal-to-noise ratio (SNR) in directly read detector data. This study proposes an anti-noise performance analysis using deep learning. End-to-end convolutional neural networks were employed to analyze noise resistance in encoded data pages captured by the detector. Experimental results demonstrate that these networks effectively correct system imaging aberrations, detector light intensity response, holographic storage medium response non-uniformity, and defocusing noise from the recording objective lens. Consequently, the BER of reconstructed encoded data pages can be reduced to 1/10 of that from direct detection, while the SNR can be increased more than fivefold, enhancing the accuracy and reliability of data reading in amplitude holographic data storage systems.

Enhancing the magnetization, dielectric parameters and elastic parameters while simultaneously minimizing coercivity and dielectric loss in nickel-manganese-cobalt ferrite nanoparticles through Ce3+ doping assistance

This study focuses on examining how the rare-earth cerium incorporation affects the magnetic, dielectric, and mechanical characteristics of Ni0.5Mn0.25Co0.25CexFe2-xO4 spinel ferrite nanoparticles. (NMCCF). The nanoferrite Ni0.5Mn0.25Co0.25Ce0.04Fe1.96O4 acquires the lowest coercivity of 567 Oe and the highest saturation magnetization of 52.23 emu/g. All the NMCCFx nanoferrites exhibit a microwave frequency range of 9.47–11.55 GHz, suggesting potential applications in longitudinal recording media and microwave absorbance. Moreover, the nanoferrite Ni0.5Mn0.25Co0.25Ce0.1Fe1.9O4 demonstrates the highest dielectric value of 1871, with an enhancing ratio of 754 %, excellent conductivity at 3.12 μ(Ω.m)−1 along with a remarkably enhanced percentage of 369 %. Additionally, it shows a loss factor of 2.17, with a notable improvement percentage of 26 % compared to the pure NMCCF0 sample at 50 Hz and room temperature. The elastic moduli (longitudinal, shear, Young, and bulk) of the Ni0.5Mn0.25Co0.25Ce0.1Fe1.9O4 nanoferrite increased from 1.21 to 2.77 GPa, 0.25–0.76 GPa, 0.68–1.99 GPa, and 0.87–1.75 GPa, respectively. This study introduces a novel approach to Ni–Mn–Co–Ce spinel nanoferrites, highlighting their magnetic, electrical, and mechanical characteristics, which hold promise for electronic and high-frequency device applications.

Perancangan Proses Bisnis Untuk Mengurangi Waste Overproduction dengan Metode Business Process Improvement pada Proses Produksi Konveksi di PT. XYZ

PT XYZ is a company engaged in the field of convection. There is a problem related to the excess of the actual production amount of 899 with a production request of 732 which indicates the occurrence of waste overproduction. This research aims to minimize waste overproduction in the production process caused by poor demand management and the process of recording the amount of production every day by workers is done manually so it is necessary to design related records in the information category. Problem solving is done by improving business processes using the Business Process Improvement method. The results of this improvement obtained a proposed business process by making improvements to the initial business process. The process of making google spreadsheet as a recording media is done using the waterfall method. The results of the google spreadsheet design can display the number of requests, cut results, and remaining products continuously so that the recording process can be done more accurately and the collected data will be safely stored in the system so that it can minimize the occurrence of overproduction