Preisach diagrams and anhysteresis: do they measure interactions?

Dunlop, David J.; Westcott-Lewis, M. F.; Bailey, Monika

doi:10.1016/0031-9201(90)90076-a

Cited by 41 publications

(47 citation statements)

References 30 publications

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“…There is no single parameter that perfectly reflects interaction field strength [Dunlop, et al, 1990], but the crossover R value of Cisowski [Cisowski, 1981] is commonly used. The 17 strength of three-dimensional magnetostatic interactions affects two parameters employed in modeling FMR spectra: the anisotropy field B an and the Gaussian linewidth σ.…”

Section: Discussionmentioning

confidence: 99%

“…Anhysteretic susceptibility, which provides a qualitative measure of inverse interaction strength when comparing single domain particles of similar volumes [Dunlop, et al, 1990;Egli and Lowrie, 2002], has also been used to distinguish bacterial magnetite chains from abiogenic magnetite [Kopp, et al, 2006;Moskowitz, et al, 1993]. Anhysteretic magnetization is acquired by the application of a small biasing field in the presence of a decaying alternating field.…”

Section: Introductionmentioning

confidence: 99%

“…The discrepancy is largely accounted for by the thermal fluctuation field, which for 100 nm cubes of magnetite at room temperature is approximately Cells of mutant AMB-1 and intact cells of wild-type AMB-1 have B c close to those predicted from the regression line, but SDS-treated cells of AMB-1 and all MV-1 samples fall well off the line. This difference may be due to a combination of imperfect fitting of the FMR spectra and the presence of additional factors not treated in the simple physical model used to predict B c .There is no single parameter that perfectly reflects interaction field strength [Dunlop, et al, 1990], but the crossover R value of Cisowski [Cisowski, 1981] is commonly used. The 17 strength of three-dimensional magnetostatic interactions affects two parameters employed in modeling FMR spectra: the anisotropy field B an and the Gaussian linewidth σ.…”

mentioning

confidence: 99%

“…The particles' narrow distribution within the single domain size range is typically observed in analyses of coercivity spectra, including the measurement of the acquisition of isothermal remanent magnetization and the demagnetization of remanent magnetizations Pan, et al, 2005]. [Egli, 2004] used the unmixing of coercivity spectra to determine the biogenic contribution to lacustrine sedimentary magnetization.Anhysteretic susceptibility, which provides a qualitative measure of inverse interaction strength when comparing single domain particles of similar volumes [Dunlop, et al, 1990;Egli and Lowrie, 2002], has also been used to distinguish bacterial magnetite chains from abiogenic magnetite [Kopp, et al, 2006;Moskowitz, et al, 1993]. Anhysteretic magnetization is acquired by the application of a small biasing field in the presence of a decaying alternating field.…”

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Ferromagnetic resonance spectroscopy for assessment of magnetic anisotropy and magnetostatic interactions: A case study of mutant magnetotactic bacteria

et al. 2006

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Ferromagnetic resonance spectroscopy (FMR) can be used to measure the effective magnetic field within a sample, including the contributions of both magnetic anisotropy and magnetostatic interactions. One particular use is in the detection of magnetite produced by magnetotactic bacteria. These bacteria produce single-domain particles with narrow size and shape distributions that are often elongated and generally arranged in chains. All of these features are detectable through FMR. Here, we examine their effects on the FMR spectra of magnetotactic bacteria strains MV-1 (which produces chains of elongate magnetite crystals), AMB-1 (which produces chains of nearly equidimensional magnetite crystals), and two novel mutants of AMB-1: mnm13 (which produces isolated, elongate crystals), and mnm18 (which produces nearly equidimensional crystals that are usually isolated). Comparison of their FMR spectra indicates that the positive magnetic anisotropy indicated by the spectra of almost all magnetotactic bacteria is a product of chain alignment and particle elongation. We also find correlations between FMR properties and magnetic measurements of coercivity and magnetostatic interactions. FMR thus provides a rapid method for assessing the magnetic properties of assemblages of particles, with applications including screening for samples likely to contain bacterial magnetofossils. Index terms: 1505 biogenic magnetic minerals, 1518 magnetic fabrics and anisotropy, 1540 rock and mineral magnetism, 0419 biomineralization, 0465 microbiology.Key words: ferromagnetic resonance spectroscopy, magnetotactic bacteria, magnetofossils, magnetic anisotropy, magnetostatic interactions, rock magnetism An edited version of this paper was published by AGU. Copyright (C) 2006 American Geophysical Union. 2 IntroductionFerromagnetic resonance spectroscopy (FMR), a form of electron spin resonance spectroscopy, can serve as a rapid technique for assessing the magnetic anisotropy of and magnetostatic interactions between individual particles in a polycrystalline sample. It is based upon the Zeeman effect, which is the splitting between electron spin energy levels that occurs in the presence of a magnetic field. The Zeeman effect allows a ground-state electron to absorb a photon with energy equal to the splitting between the energy states. In a magnetic material, magnetic anisotropy (whether magnetocrystalline, shape, or stress-induced) and interparticle interactions contribute to the energy of the particles within a sample and thereby alter the resonance energy. As a result, FMR can be used to probe these parameters [Griscom, 1974;Griscom, 1981;Kittel, 1948;Kopp, et al., 2006;Schlömann, 1958;Weiss, et al., 2004].Techniques for measuring anisotropy and magnetostatic interactions have a number of applications in the field of rock magnetism. The example on which we will focus here is the identification of magnetite produced by magnetotactic bacteria, a topic of great interest for understanding the magnetization of sediments. Fossil magnetotactic bacte...

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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confidence: 99%

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Ferromagnetic resonance spectroscopy for assessment of magnetic anisotropy and magnetostatic interactions: A case study of mutant magnetotactic bacteria

et al. 2006

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“…The samples under study have a layered structure, with a varying spacing between magnetic layers, so the resulting diagrams are quite interesting. It is, of course, a matter of interpretation, which is still under investigation [5], what can be seen on Preisach diagrams. …”

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Preisach Maps of Multilayered Co/Cu Structures

Gutowski¹,

Gutowska²,

Piotrowski³

et al. 2000

Acta Phys. Pol. A

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Magnetooptical Kerr effect measurements of room temperature hysteresis loops were taken using sandwich-and multilayer-type specimens and He-Ne laser light. For maximal external field of 250 Gs the corresponding Kerr angle reached 0.04 deg. The samples were obtained in the Institute of Physics, Polish Academy of Sciences, Warszawa, using MBE method. The structure of samples may be described by a formula: substrate-buffer layer-(zCo/yCu)n,-cουer lαyer. Αl2 O3 (two orientations) and MgO were used as substrates, the buffer layer was made of W, Cu or Fe, x = 15, 20 or 25 Å, y = 7, 8, 9, 10, 11, 12, 13, 14, and 20 A, n = 25 and 30. 50A of gold (Au) served as a cover layer. The genetic algorithm was subsequently used as a data processing tool, in order to reconstruct the Preisach map for each hysteresis loop. The diagrams clearly indicate changes of magnetic interactions caused by varying thicknesses of individual magnetic and non-magnetic layers.PACS numbers: 75.40. Mg, 75.60.Ej, 78.20.Ls, 78.66.-w 1. Introduction The idea of finding an analytical formula describing the hysteresis loop for magnetic materials is rather old. The elegant solution, first proposed by Preisach [1] in 1935, was not immediately put into practice due to the lack of satisfactory computing power available then. It was relatively easy to simulate the hysteresis curve havmg the Preisach map, but the inverse was (and still is) rather difficult. Only in 1950's first more or less successful attempts to solve this problem were reported [2][3][4]. After 1960 more papers dealing with related subjects appeared, almost all of them proposed various improvements and extensions of original Preisach's idea.In this paper we present Preisach maps obtained by a genetic algorithm and using only one simple a priori assumption concerning the Preisach density. The samples under study have a layered structure, with a varying spacing between magnetic layers, so the resulting diagrams are quite interesting. It is, of course, a matter of interpretation, which is still under investigation [5], what can be seen on Preisach diagrams.

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Understanding fine magnetic particle systems through use of first-order reversal curve diagrams

et al. 2014

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First-order reversal curve (FORC) diagrams are constructed from a class of partial magnetic hysteresis loops known as first-order reversal curves and are used to understand magnetization processes in fine magnetic particle systems. A wide-ranging literature that is pertinent to interpretation of FORC diagrams has been published in the geophysical and solid-state physics literature over the past 15 years and is summarized in this review. We discuss practicalities related to optimization of FORC measurements and important issues relating to the calculation, presentation, statistical significance, and interpretation of FORC diagrams. We also outline a framework for interpreting the magnetic behavior of magnetostatically noninteracting and interacting single domain, superparamagnetic, multidomain, single vortex, and pseudosingle domain particle systems. These types of magnetic behavior are illustrated mainly with geological examples relevant to paleomagnetism, rock magnetism, and environmental magnetism. These technical, experimental, and interpretational considerations are relevant to applications that range from improving particulate media for magnetic recording in materials science, to providing a foundation for understanding geomagnetic recording by rocks in geophysics, to interpreting depositional, microbiological, and environmental processes in sediments.

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Preisach diagrams and anhysteresis: do they measure interactions?

Cited by 41 publications

References 30 publications

Ferromagnetic resonance spectroscopy for assessment of magnetic anisotropy and magnetostatic interactions: A case study of mutant magnetotactic bacteria

Ferromagnetic resonance spectroscopy for assessment of magnetic anisotropy and magnetostatic interactions: A case study of mutant magnetotactic bacteria

Preisach Maps of Multilayered Co/Cu Structures

Understanding fine magnetic particle systems through use of first-order reversal curve diagrams

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