scholarly journals Micromagnetic simulations of first-order reversal curve (FORC) diagrams of framboidal greigite

2020 ◽  
Vol 222 (2) ◽  
pp. 1126-1134
Author(s):  
Miguel A Valdez-Grijalva ◽  
Lesleis Nagy ◽  
Adrian R Muxworthy ◽  
Wyn Williams ◽  
Andrew P Roberts ◽  
...  
Keyword(s):  
Magnetic Response ◽  
Environmental Indicator ◽  
Micromagnetic Simulations ◽  
First Order ◽  
Forc Diagram ◽  
Magnetostatic Interactions

SUMMARY Greigite is a sensitive environmental indicator and occurs commonly in nature as magnetostatically interacting framboids. Until now only the magnetic response of isolated non-interacting greigite particles have been modelled micromagnetically. We present here hysteresis and first-order reversal curve (FORC) simulations for framboidal greigite (Fe3S4), and compare results to those for isolated particles of a similar size. We demonstrate that these magnetostatic interactions alter significantly the framboid FORC response compared to isolated particles, which makes the magnetic response similar to that of much larger (multidomain) grains. We also demonstrate that framboidal signals plot in different regions of a FORC diagram, which facilitates differentiation between framboidal and isolated grain signals. Given that large greigite crystals are rarely observed in microscopy studies of natural samples, we suggest that identification of multidomain-like FORC signals in samples known to contain abundant greigite could be interpreted as evidence for framboidal greigite.

scholarly journals FORC-Diagram Analysis for a Step-like Magnetization Reversal in Nanopatterned Stripe Array

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7523
Author(s):  
Victor K. Belyaev ◽  
Dmitry Murzin ◽  
Jose C. Martínez-García ◽  
Montserrat Rivas ◽  
Nikolay V. Andreev ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Distribution Model ◽  
Fabrication Method ◽  
Switching Field ◽  
Magnetic Microstructure ◽  
Micromagnetic Simulations ◽  
First Order ◽  
Magnonic Crystal ◽  
Forc Diagram ◽  
Diagram Analysis

The fabrication approach of a magnonic crystal with a step-like hysteresis behavior based on a uniform non-monotonous iron layer made by shadow deposition on a preconfigured substrate is reported. The origin of the step-like hysteresis loop behavior is studied with local and integral magnetometry methods, including First-Order Reversal Curves (FORC) diagram analysis, accompanied with magnetic microstructure dynamics measurements. The results are validated with macroscopic magnetic properties and micromagnetic simulations using the intrinsic switching field distribution model. The proposed fabrication method can be used to produce magnonic structures with the controllable hysteresis plateau region’s field position and width that can be used to control the magnonic crystal’s band structure by changing of an external magnetic field.

FORC analysis of magnetically soft microparticles embedded in a polymeric elastic environment

2022 ◽  
Author(s):  
Dmitry Yu Borin ◽  
Mikhail V Vaganov
Keyword(s):  
Particle Concentration ◽  
Magnetic Hysteresis ◽  
Magnetic Response ◽  
Soft Matrix ◽  
First Order ◽  
Matrix Elasticity ◽  
Intrinsic Coercivity ◽  
The Matrix ◽  
Soft Particles ◽  
Elastomer Composites

Abstract First-order reversal curve (FORC) analysis allows one to investigate composite magnetic materials by decomposing the magnetic response of a whole sample into individual responses of the elementary objects comprising the sample. In this work, we apply this technique to analysing silicone elastomer composites reinforced with ferromagnetic microparticles possessing low intrinsic coercivity. Even though the material of such particles does not demonstrate significant magnetic hysteresis, the soft matrix of the elastomers allows for the translational mobility of the particles and enables their magnetomechanical hysteresis which renders into a wasp-waisted major magnetization loop of the whole sample. It is demonstrated that the FORC diagrams of the composites contain characteristic wing features arising from the collective hysteretic magnetization of the magnetically soft particles. The influence of the matrix elasticity and particle concentration on the shape of the wing feature is investigated, and an approach to interpreting experimental FORC diagrams of the magnetically soft magnetoactive elastomers is proposed. The experimental data are in qualitative agreement with the results of the simulation of the particle magnetization process obtained using a model comprised of two magnetically soft particles embedded in an elastic environment.

scholarly journals Magnetic switching of nanoscale antidot lattices

2016 ◽  
Vol 7 ◽  
pp. 733-750 ◽  
Author(s):  
Ulf Wiedwald ◽  
Joachim Gräfe ◽  
Kristof M Lebecki ◽  
Maxim Skripnik ◽  
Felix Haering ◽  
...  
Keyword(s):  
Nanosphere Lithography ◽  
Magnetic Film ◽  
Micromagnetic Simulations ◽  
First Order ◽  
Magnetic Switching ◽  
Out Of Plane ◽  
Magnetic Microscopy ◽  
The Rich ◽  
Microscopy Techniques

We investigate the rich magnetic switching properties of nanoscale antidot lattices in the 200 nm regime. In-plane magnetized Fe, Co, and Permalloy (Py) as well as out-of-plane magnetized GdFe antidot films are prepared by a modified nanosphere lithography allowing for non-close packed voids in a magnetic film. We present a magnetometry protocol based on magneto-optical Kerr microscopy elucidating the switching modes using first-order reversal curves. The combination of various magnetometry and magnetic microscopy techniques as well as micromagnetic simulations delivers a thorough understanding of the switching modes. While part of the investigations has been published before, we summarize these results and add significant new insights in the magnetism of exchange-coupled antidot lattices.

Magnetostatic Interactions and Coercivities of Ferromagnetic Soft Nanowires in Uniform Length Arrays

2008 ◽  
Vol 8 (6) ◽  
pp. 2944-2954 ◽  
Author(s):  
F. Béron ◽  
L. Clime ◽  
M. Ciureanu ◽  
D. Ménard ◽  
R. W. Cochrane ◽  
...  
Keyword(s):  
Nanowire Arrays ◽  
Physical Parameters ◽  
Preisach Model ◽  
General Shape ◽  
First Order ◽  
Average Value ◽  
Interaction Field ◽  
Soft Ferromagnetic ◽  
Out Of Plane ◽  
Magnetostatic Interactions

First-order reversal curve diagrams have been used to investigate magnetostatic interactions and average coercivity of individual wires in soft ferromagnetic uniform length nanowire arrays. We present a method for identifying these physical parameters on the out-of-plane first-order reversal curve diagrams: the position of the irreversible part on the critical axis is a good approximation to the average value of the nanowire coercivity and the maximum interaction field is equal to the interaction field at saturation. Their dependence upon material (CoFeB and Ni) and nanowire length are presented. The magnetostatic interactions increase linearly with length, in agreement with a model developed previously. The global array coercivity, obtained from magnetization curves, is generally lower than the apparent average coercivity for individual nanowires. This coercivity reduction increases linearly with the magnetostatic interactions. The general shape of the out-of-plane first-order reversal curve diagrams is compared with those obtained from a theoretical moving Preisach model.

scholarly journals Micromagnetic simulations of first-order reversal curves in nanowire arrays using MuMax3

AIP Advances ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 125130
Author(s):  
R. G. Eimerl ◽  
K. S. Muster ◽  
R. Heindl
Keyword(s):  
Nanowire Arrays ◽  
Micromagnetic Simulations ◽  
First Order
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