Modification of Magnetic Characteristics of Polycrystalline Nife Films at the Irradiation Laser Pulses and Formation of Regular Structure of Magnetic Nanoislands

We report the formation of a sole long nanowire structure and the regular nanowire arrays inside a groove on the surface of Fe-based metallic glass upon irradiation of two temporally delayed femtosecond lasers with the identical linear polarization parallel and perpendicular to the groove, respectively. The regular structure formation can be well observed within the delay time of 20 ps for a given total laser fluence of F = 30 mJ/cm2 and within a total laser fluence range of F = 30–42 mJ/cm2 for a given delay time of 5 ps. The structural features, including the unit width and distribution period, are measured on a one-hundred nanometer scale, much less than the incident laser wavelength of 800 nm. The degree of structure regularity sharply contrasts with traditional observations. To comprehensively understand such phenomena, we propose a new physical model by considering the spin angular momentum of surface plasmon and its enhanced inhomogeneous magnetization for the ferromagnetic metal. Therefore, an intensive TE polarized magnetic surface wave is excited to result in the nanometer-scaled energy fringes and the ablative troughs. The theory is further verified by the observation of nanowire structure disappearance at the larger time delays of two laser pulses.

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INFLUENCE OF DEFECTS ON MAGNETIC CHARACTERISTICS OF FERRITE-GARNET FILMS

Physical and Chemical Aspects of the Study of Clusters Nanostructures and Nanomaterials ◽

10.26456/pcascnn/2020.12.103 ◽

2020 ◽

pp. 103-112

Author(s):

Александра Ивановна Иванова ◽

Елена Михайловна Семенова ◽

Галина Григорьевна Дунаева ◽

Сергей Вадимович Овчаренко ◽

Сергей Андреевич Третьяков ◽

...

Keyword(s):

Coercive Force ◽

Laser Action ◽

Mechanical Damage ◽

Fold Increase ◽

Laser Pulses ◽

Magnetic Films ◽

Femtosecond Laser Pulses ◽

Magnetic Characteristics ◽

Garnet Films ◽

Bulk Film

В работе рассмотрено влияние объемных дефектов, связанных с локальным механическим повреждением и термическим лазерным воздействием, на доменную структуру и магнитные характеристики эпитаксиальных висмутсодержащих магнитных пленок феррит-граната (Bi :ФГ). Установлено, что одноосные пленки Bi: ФГ устойчивы к объемным дефектам, размер которых не превышает ширину доменов пленки. Показано, что рассмотренные объемные дефекты пленки оказывают влияние на процесс намагничивания пленки, ход кривых намагничивания, на величину коэрцитивной силы. Воздействие лазерным импульсом с плотностью мощности 800 Дж/см приводит к увеличению коэрцитивной силы локального участка пленки в 4 раза (с 0,33 Э до 1,44 Э) This paper presents a study of the effect of volumetric (bulk) defects associated with the local mechanical damage and thermal laser action on the domain structure and magnetic characteristics of epitaxial bismuth-containing garnet-ferrite (Bi: FG) magnetic films. It was found that uniaxial Bi: FG films are resistant to bulk defects, the size of which does not exceed the width of the film domains. It is shown that the considered bulk film defects affect the process of the film magnetization, the form of the magnetization curves, the magnitude of the coercive force and the ratio of the displacement field to the coercive force. Effect of femtosecond laser pulses exposure with a power density of 800 J/cm on the coercivity of film was found. The 4 - fold increase of the coercive field near a defect is discovered (from 0,33 Oe to 1,44 Oe).

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Magnetic Force Microscopy Study of Multiscale Ion-Implanted Platinum in Silica Glass, Recorded by an Ultrafast Two-Wave Mixing Configuration

Microscopy and Microanalysis ◽

10.1017/s1431927619015204 ◽

2019 ◽

Vol 26 (1) ◽

pp. 53-62

Author(s):

David Torres-Torres ◽

Jhovani Bornacelli ◽

Oscar Vega-Becerra ◽

Andres M. Garay-Tapia ◽

Francisco S. Aguirre-Tostado ◽

...

Keyword(s):

Magnetic Force Microscopy ◽

Magnetic Force ◽

Magnetic Measurements ◽

Laser Pulses ◽

Magnetic Characteristics ◽

Gradient Force ◽

Magnetic Storage ◽

Force Microscopy ◽

Pure Silica ◽

Periodic Linear

AbstractThis study explores magnetization exhibited by nanoscale platinum-based structures embedded in pure silica plates. A superposition of laser pulses in the samples produced periodic linear arrangements of micro-sized structures. The samples were integrated by PtO2 microstructures (PtOΣs) with dispersed Pt oxide nanoparticles in their surroundings. The characterization of the materials was performed by high transmission electron microscopy studies. Furthermore, topographical and magnetic effects on the sample surfaces were analyzed by atomic force microscopy and magnetic force microscopy, respectively. The magnetic measurements indicated an enhancement in the gradient phase shift and in the gradient force related to the magnetic PtOΣs. The possibility of tuning the magnetic characteristics of the samples through contact with a Nd2Fe14B magnet was demonstrated. This process corresponds to an innovative method for obtaining magnetic PtOΣs induced by laser pulses. Moreover, an increase in the compactness of the silica with platinum-based structures was confirmed by an evaluation of the effective elastic modulus with reference to pure silica. The multimodal magnetic structures studied in this work seem to be candidates for developing high-density magnetic storage media.

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Interrelationship of the cellular distribution and secretion of regular structure (RS) protein in Bacillus licheniformis nm 105

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100123969 ◽

1992 ◽

Vol 50 (1) ◽

pp. 712-713

Author(s):

Xiaorong Zhu ◽

Richard McVeigh ◽

Bijan K. Ghosh

Keyword(s):

Alkaline Phosphatase ◽

Bacillus Licheniformis ◽

Self Assembly ◽

Gel Electrophoresis ◽

Culture Supernatant ◽

Regular Structure ◽

The Self ◽

Cellular Distribution ◽

Structural Protein ◽

Laboratory Cultures

A mutant of Bacillus licheniformis 749/C, NM 105 exhibits some notable properties, e.g., arrest of alkaline phosphatase secretion and overexpression and hypersecretion of RS protein. Although RS is known to be widely distributed in many microbes, it is rarely found, with a few exceptions, in laboratory cultures of microorganisms. RS protein is a structural protein and has the unusual properties to form aggregate. This characteristic may have been responsible for the self assembly of RS into regular tetragonal structures. Another uncommon characteristic of RS is that enhanced synthesis and secretion which occurs when the cells cease to grow. Assembled RS protein with a tetragonal structure is not seen inside cells at any stage of cell growth including cells in the stationary phase of growth. Gel electrophoresis of the culture supernatant shows a very large amount of RS protein in the stationary culture of the B. licheniformis. It seems, Therefore, that the RS protein is cotranslationally secreted and self assembled on the envelope surface.

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A TEM microscopical investigation of the magnetic domain structure of a metastable austenitic stainless steel

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100171213 ◽

1994 ◽

Vol 52 ◽

pp. 696-697

Author(s):

G. Fourlaris ◽

T. Gladman

Keyword(s):

Tensile Strength ◽

Stainless Steel ◽

Austenitic Stainless Steel ◽

Cold Rolling ◽

Solution Treatment ◽

Magnetic Domain ◽

High Strength ◽

Medium Carbon Steel ◽

Magnetic Characteristics ◽

Metastable Austenitic Stainless Steel

Stainless steels have widespread applications due to their good corrosion resistance, but for certain types of large naval constructions, other requirements are imposed such as high strength and toughness , and modified magnetic characteristics.The magnetic characteristics of a 302 type metastable austenitic stainless steel has been assessed after various cold rolling treatments designed to increase strength by strain inducement of martensite. A grade 817M40 low alloy medium carbon steel was used as a reference material.The metastable austenitic stainless steel after solution treatment possesses a fully austenitic microstructure. However its tensile strength , in the solution treated condition , is low.Cold rolling results in the strain induced transformation to α’- martensite in austenitic matrix and enhances the tensile strength. However , α’-martensite is ferromagnetic , and its introduction to an otherwise fully paramagnetic matrix alters the magnetic response of the material. An example of the mixed martensitic-retained austenitic microstructure obtained after the cold rolling experiment is provided in the SEM micrograph of Figure 1.

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