Barium hexaferrite/muscovite heteroepitaxy with mechanically robust perpendicular magnetic anisotropy

Recent advances in the design and development of magnetic storage devices have led to an enormous interest in materials with perpendicular magnetic anisotropy (PMA) property. The past decade has witnessed a huge growth in the development of flexible devices such as displays, circuit boards, batteries, memories, etc. since they have gradually made an impact on people’s lives. Thus, the integration of PMA materials with flexible substrates can benefit the development of flexible magnetic devices. In this study, we developed a heteroepitaxy of BaFe12O19 (BaM)/muscovite which displays both mechanical flexibility and PMA property. The particular PMA property was characterized by vibrating sample magnetometer, magnetic force microscopy, and x-ray absorption spectroscopy. To quantify the PMA property of the system, the intrinsic magnetic anisotropy energy density of ~2.83 Merg cm−3 was obtained. Furthermore, the heterostructure exhibits robust PMA property against severe mechanical bending. The findings of this study on the BaM/muscovite heteroepitaxy have several important implications for research in next-generation flexible magnetic recording devices and actuators.

From discrete element simulation data to process insights

Industrial-scale discrete element simulations typically generate Gigabytes of data per time step, which implies that even opening a single file may require 5 - 15 minutes on conventional magnetic storage devices. Data science’s inherent multi-disciplinary nature makes the extraction of useful information challenging, often leading to undiscovered details or new insights. This study explores the potential of statistical learning to identify potential regions of interest for large scale discrete element simulations. We demonstrate that our in-house knowledge discovery and data mining system (KDS) can decompose large datasets into i) regions of potential interest to the analyst, ii) multiple decompositions that highlight different aspects of the data, iii) simplify interpretation of DEM generated data by focusing attention on the interpretation of automatically decomposed regions, and iv) streamline the analysis of raw DEM data by letting the analyst control the number of decomposition and the way the decompositions are performed. Multiple decompositions can be automated in parallel and compressed, enabling agile engagement with the analyst’s processed data. This study focuses on spatial and not temporal inferences.

Green Synthesis of Tungsten Ditelluride and the Magnetoresistance Property

As a new type of unsaturated linear magnetoresistive materials, tungsten ditelluride series material has potential applications in the fields of strong magnetic detection, information recording and magnetic storage devices. The current development concepts of “green materials”, “green chemical technology” and “environmentally friendly technology” require us to pursue the non-toxic, low-emission and non-emission in material synthesis technology. At the same time, the prepared products show excellent performance and high versatility and efficiency. According to our previous work, the study attempts to use a low-volatile amine solvent as a pretreatment raw material to synthesize a tungsten germanium-based linear magnetoresistive material by hydrothermal/solvothermal method and self-fluxing method. The obtained materials were subjected to XRD, Raman, SEM and Magnetoresistance. Experimental results show that when the mass ratio of W and Te is 1:4, the prepared material is pure phase and the sample is the layered structure. The Magnetoresistance Property points out that the maximum value is about 190 %, which appears in the condition of 10 K and 7 T. Those test projects include phase, structure and morphology characteristics, and provide technical parameters and methods for the development of green synthesis and potential applications of tungsten ditelluride series linear magnetoresistive materials.

Enhancing the power of quality issues using superconducting magnetic storage devices–based dynamic voltage restorer–aided switched coupled inductor inverter with space vector pulse width modulation techniques

This paper emphasizes on proposing a dynamic voltage restorer–based superconducting magnetic storage devices have utilized to power quality issues. Dynamic voltage restorer can be used for different topologies of the inverter. The conventional topology of dynamic voltage restorer possessing voltage source inverter or Z-source inverter is modified into a switched coupled inductor inverter which has the clear edge in power transfer over the former. The versatility of the controller is enhanced by this work by deploying a fuzzy combine discrete wavelet transforms. The proposed system in this paper, switched coupled inductor inverter–based dynamic voltage restorer-superconducting magnetic storage devices on mitigating the interruption, harmonics and voltage sag/swell. The operating of switched coupled inductor inverter has buck/boost function capability and reduced number of passive components. Due to digitalization, higher utilization factor and reduced harmonic content, controller of fuzzy logic–space vector pulse width modulation techniques with filter application of discrete wavelet transform is used to operate of switched coupled inductor inverter. The hysteresis controller is used to perform the superconducting magnetic storage devices device, has the ability in the storage of real power with high energy density and protects the consumer from grid fluctuation. To detect the power quality disturbances quickly response and improve the compensation capability of dynamic voltage restorer-superconducting magnetic storage devices. The whole of the suggested system is simulated in MATLAB/Simulink and realized as a prototype whose control pulses are duly generated and fed by dSPACE 1104 controller.

Fe1-xNix Alloy Nanoparticles Encapsulated Inside Carbon Nanotubes: Controlled Synthesis, Structure and Magnetic Properties

In the present work, different synthesis procedures have been demonstrated to fill carbon nanotubes (CNTs) with Fe1-xNix alloy nanoparticles (x = 0.33, 0.5). CNTs act as templates for the encapsulation of magnetic nanoparticles, and provide a protective shield against oxidation as well as prevent nanoparticles agglomeration. By variation of the reaction parameters, the purity of the samples, degree of filling, the composition and size of filling nanoparticles have been tailored and therefore the magnetic properties. The samples were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Bright-field (BF) TEM tomography, X-ray powder diffraction, superconducting quantum interference device (SQUID) and thermogravimetric analysis (TGA). The Fe1-xNix-filled CNTs show a huge enhancement in the coercive fields compared to the corresponding bulk materials, which make them excellent candidates for several applications such as magnetic storage devices.

Wear Modeling of Nanometer Thick Protective Coatings

Use of nanometer thin films has received significant attention in recent years because of their advantages in controlling friction and wear. There have been significant advances in applications such as magnetic storage devices, and there is a need to explore new materials and develop experimental and theoretical frameworks to better understand nanometer thick coating systems, especially wear characteristics. In this work, a finite element model is developed to simulate the sliding wear between the protruded pole tip in a recording head (modeled as submicrometer radius cylinder) and a rigid asperity on the disk surface. Wear is defined as plastically deformed asperity and material yielding. Parametric studies reveal the effect of the cylindrical asperity geometry, material properties, and contact severity on wear. An Archard-type wear model is proposed, where the wear coefficients are directly obtained through curve fitting of the finite element model, without the use of an empirical coefficient. Limitations of such a model are also discussed.