V. P. Shcherbakov

V. P. Shcherbakov
Russian Academy of Sciences | RAS · Geophysical Observatory Borok of Institute of Physics of the Eart5h

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Publications

Publications (125)
Article
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We present new results of geochronological, rock magnetic, paleomagnetic and paleointensity studies of the olivine gabbro dyke located at the northern part of the Murmansk craton, NE Fennoscandia (the Kola Peninsula). According to its geochemistry, petrographic and geochronology features, the dyke belongs to the 2.68 Ga dyke swarm, what is confirme...
Article
A collection of igneous rocks from the Ukrainian Shield sampled from the Korsun-Novomyrhorod pluton (age interval 1760–1735 Ma, Ingul Domain) and from the Korosten pluton (age 1760–1750 Ma, North-Western Domain) is studied. To obtain reliable determinations of paleointensity (Banc), the magnetic and thermomagnetic properties of samples were studied...
Article
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Plain Language Summary Volcanic rocks, the magnetic minerals of which can acquire a thermoremanent magnetization (TRM) from Earth's magnetic field during their initial cooling, are essential to constrain the working of the geodynamo through Earth's history. However, if the rock is subsequently reheated at moderate temperature in another ambient fie...
Presentation
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The geomagnetic field, generated by a dynamo in the Earth’s outer core, have significantly changed its strength (absolute palaeointensity, API) and frequency of polarity reversals through geological time. These changes are likely controlled by the geometry of the core, the thermal boundary conditions imposed by the mantle on the core, and/or bifurc...
Article
Numerical simulation of the process of remagnetization of small pseudo–single-domain magnetite particles ( Т c = 580°С) was performed. The particles are cylindrical in shape, with a height h of 60–350 nm and a height-to-diameter ratio of 1.29. This geometry enables preferential anisotropy of the shape, causing the magnetic moment of the particle to...
Article
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Estimating the time of formation of the Earth’s solid inner core is a first–order problem in the thermal evolution of the Earth as a planet, which can be solved in particular by paleointensity (Banc) determinations. For this purpose, we have studied a collection of ~1380 Ma rocks sampled in the Udzha River valley within the Udzha aulacogen from the...
Article
A new approach to the solution of kinetic equations describing the process of formation of anhysteretic remanent magnetization (ARM) is proposed, which made it possible to accelerate the numerical calculation of the process of formation of ARM by two orders of magnitude for uniaxial oriented non-interacting single-domain particles, while practicall...
Article
The evolution of the domain structure (DS) of cubic submicron- and micron-sized magnetite particles has been studied in detail during “cooling” of specimens from the Curie temperature Тс to room temperature Тr followed by their “reheating” to Тс in order to determine the degree of irreversibility of DS changes during heat treatment and their possib...
Article
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Changes of the geomagnetic field over geologic time scales can be used to study the evolution and processes of its sources in Earth's deep interior. As a stark contrast to the geomagnetic field behaviour of the recent past, the field in the late Neoproterozoic is defined by ambiguous polar wander paths, ultra-low field strengths and a period of ext...
Article
Changes in palaeosecular variation, dipole moment and polarity reversal frequency are salient features of the Earth’s magnetic field over the geological past, yet how these changes are linked by the geodynamo remains controversial. To further understand this issue, we provide new absolute (API) and relative (RPI) palaeointensities from the ∼1-km-th...
Article
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We conducted an absolute paleointensity survey on 74 lava flows from the Okhotsk–Chukotka Volcanic Belt (NE Russia), emplaced 90–83 Ma toward the end of the Cretaceous Normal Superchron (CNS, 121–84 Ma). Relying on preliminary results, we restricted our analysis to eight lava flows (140 Thellier–Coe experiments), two of which also yielded successfu...
Article
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—The experiments have been carried out on the acquisition of thermochemical remanent magnetization (TCRM) in basalt samples containing titanomagnetite (TM) with the Curie temperature Т с ~200°C by their rapid heating to maximum temperatures Т * from 450 to 530°C followed by slow cooling in the laboratory magnetic field B lab . At different stages o...
Article
The time-averaged geomagnetic field is generally purported to be uniformitarian across Earth history—close to a geocentric axial dipole, with average strength within one order of magnitude of that at present. Nevertheless, recent studies have reported that the field was approximately ten times weaker than present in the mid-Palaeozoic (∼410–360 Ma)...
Article
Monte Carlo numerical simulation of the formation of chemical remanent magnetization (CRM) by the mechanism of the growth of volumes from superparamagnetic (SPM) to single-domain (SD) in the ensembles of magnetostatically interacting particles, thermoremanent magnetization (TRM), and experiments on determining paleointensity by the Thellier–Coe and...
Article
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We investigated the acquisition of thermochemical remanent magnetization (TCRM) on basaltic rocks from the volcanic island of São Tomé (Gulf of Guinea) and from the southern part of the Red Sea Rift, both containing homogeneous titanomagnetite grains with Curie temperatures of 100–200 °C. The TCRM was created in a rotating thermomagnetometer by coo...
Article
S U M M A R Y We conducted an absolute palaeointensity (API) survey on Ethiopian volcanics from Early Oligocene (Belessa section) and Middle Miocene (Debre Sina section). After a careful selection based on the reversibility of high-field thermomagnetic curves from samples yielding unambiguous palaeodirections, we restricted our analysis to five (re...
Article
The consistency of the empirical data on the paleointensity and paleoinclinations contained in the BOROKPINT paleointensity world database with the Geocentric Axial Dipole (GAD) hypothesis and the Giant Gaussian Process (GGP) model describing the geomagnetic field variations in the Brunhes epoch is tested. The calculation procedure is based on the...
Article
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Abstract. The massive occurrence of the reversed middle-temperature component was found at temperatures 250-450°C during the standard stepwise thermal demagnetization of the paleomagnetic samples of dolerites from the Permian-Triassic Siberian Traps intrusive bodies. At the same time, this reversed component was not detected during AF cleaning,whil...
Article
The results of paleomagnetic studies and paleointensity determinations from two Neoarchaean Shala dikes with an age of ~2504 Ma, located within the Vodlozerskii terrane of the Karelian craton, are presented. The characteristic components of primary magnetization with shallow inclinations I = −5.7 and 1.9 are revealed; the reliability of the determi...
Article
The results of the Thellier–Coe experiments on paleointensity determination on the samples which contain chemical remanent magnetization (CRM) created by thermal annealing of titanomagnetites are reported. The results of the experiments are compared with the theoretical notions. For this purpose, Monte Carlo simulation of the process of CRM acquisi...
Poster
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The Boring Volcanic Field of the Pacific Northwest, composed of more than 80 eruptive units ranging in age from 3200 to 60 ka, offers a unique possibility to investigate the variability of the recent palaeomagnetic field. To complement previous work on palaeodirections, we conducted 240 absolute palaeointensity experiments with the joint use of the...
Article
The results of the experimental studies on creating chemical and partial thermal remanent magnetizations (or their combination), which are imparted at the initial stage of the laboratory process of the oxidation of primary magmatic titanomagnetites (Tmts) contained in the rock, are presented. For creating chemical remanent magnetization, the sample...
Article
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Defining variations in the behaviour of the geomagnetic field through geological time is critical to understanding the dynamics of Earth's core and its response to mantle convection and planetary evolution. Furthermore, the question of whether the axial dipole dominance of the recent palaeomagnetic field persists through the whole of Earth's histor...
Article
The reliability of the Thellier method for determining the paleointensity of a geomagnetic field is explored on recent igneous rocks of Kamchatka. The main magnetic mineral in the studied rocks is titanomagnetite with different degree of oxidation. It is obtained that the reliability of the results can be assessed based on the deviations of the che...
Article
The quadrature formula is obtained for the distribution function (DF) of the intensity of the geomagnetic field B and the corresponding virtual axial dipole moment VADM in the model of the Giant Gaussian Process (GGP). The predictions of this model are compared, up to a high degree of detail, with the empirical data for the Brunhes Epoch, which are...
Article
Full-text available
A spatially averaged mean-field model for fully or partially ordered members of the ilmenite–hematite solid solution series is rigorously derived from the Heisenberg Hamiltonian by first assuming no temporal correlation of atomic spins, and then by spatially averaging over spins at equivalent atomic positions. The model is based on the geometry of...
Article
A complex study is carried out for the collection of trap rocks sampled from two sequences in the geographically distant regions of the Siberian trap province: the Ergalakh section (Norilsk region) and Tyvankitskii and Delkanskii formations (Maymecha-Kotuy region). The magnetic and thermomagnetic properties are studied, petrographic and microscopic...
Article
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Petromagnetic and thermomagnetic properties of 13 dunite samples from the Pekul’ney Complex in the central Chukotka Peninsula, NE Russia, were measured to gain insight into the potentialities of thermomagnetic techniques in application to studying ultramafic rocks. Dunite currently found in layered tabular ultramafite bodies was produced in the low...
Article
Palaeointensity study of the Proterozoic-Archean volcanic rocks from the Kaapvaal Craton South Africa) are reported. Palaeomagnetic study of this collection was performed earlier by Olsson et al. Electron microscope observations, thermomagnetic and hysteresis measurements indicate the presence of single-domain and pseudo-single-domain (SD-PSD) magn...
Article
The results of numerical modeling of the geomagnetic secular variation by the method of the Giant Gaussian Process (GGP) are presented and compared with the information derived from the presentday databases for paleointensity. The variances of the positions of the virtual geomagnetic pole (VGP) calculated from the synthetic and experimental data (B...
Article
A detailed analysis of the data on the intensity of the geomagnetic dipole and frequency of its reversals presented in the world’s paleointensity databases provided the arguments in favor of the hypothesis of the negative correlation between the average virtual dipole moment (VDM) and the frequency of the reversals on the interval from 5 Ma to 100...
Article
Natural rocks and synthetic analogues can contain extremely small scaled magnetic minerals varying in shape from approximately equidimensional nanoparticles to lower dimensionally shaped lamellae resembling thin films or whiskers. The magnetic ordering temperatures of such nanomagnetic structures can significantly depend on their size and shape. H...
Article
The measurement of Curie or Néel temperatures is one of the central techniques in rock magnetism, because it is a relatively fast and reliable method to determine the predominant magnetic minerals in natural samples, even if their concentrations are relatively small. Unfortunately, the results of different commonly used measurement protocols for th...
Article
A combined palaeodirectional and palaeointensity study of a representative collection from the Bushveld Igneous Complex from 27 dolerite dykes from the 2.9, 2.7, and 1.8 Ga age swarms radiating SE, E and NE, respectively [Olsson et al., 2010] was carried out. Conventional progressive thermal or AF demagnetization was applied to all specimens. The p...
Article
A combined palaeodirectional and palaeointensity study of a representative collection of plutonic rocks from the Antarctic Peninsula batholith from the western part of the Antarctic Peninsula, near the Ukrainian Antarctic base 'Academik Vernadsky' were carried out. Petrographically, the collection includes gabbros, diorites and quartz diorites, ton...
Article
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Проведено комплексне палеомагнітне дослідження представницької колекції інтрузивних порід західної частини Антарктичного півострова (район станції Академік Вернадський). За хімічним складом колекція в основному представлена габроїдами, діоритами і кварцовими діоритами, гранодіоритами і гранітами. Вік вивчених комплексів коливається від 50 до 117 мл...
Article
The sequence of durations of the geomagnetic polarity intervals is often described in terms of a nonhomogenous Poisson process with time-dependent reversal rate, reflecting the nonstationarity of the underlying geodynamo process. This view has recently been challenged, and here we show that the first-passage time statistics of random walks taking p...
Article
Full-text available
A representative collection of Cretaceous rocks of Mongolia is used for the study of the magnetic properties of the rocks and for determination of the paleodirections and paleointensities H anc of the geomagnetic field. The characteristic NRM component in the samples is recognized in the temperature interval from 200 to 620–660°C. The values of H a...
Article
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The purpose of our work was to obtain the most possible detailed information about the composition, concentration, and structural features of the magnetic minerals contained in the rock to reveal the differences in the magnetic properties of the peridotites under various circumstances of the mantle magmatism and different conditions of metamorphism...
Article
We present the results of analyzing a representative collection of the middle Miocene 12.4–10.0 Ma basalts that compose the volcanic cover of the Shufan and Sovgavan plateaus, namely the Nikolo-L’vovsk (NL) and Sovetskaya Gavan (SG) volcanic fields. Preliminary data are obtained about the relicts of some volcanic edifices within the West and East S...
Article
In contrast to the predominant paradigm, recent studies indicate that the lengths of polarity intervals do not follow Poisson statistics, not even if non-stationary Poisson processes are considered. It is here shown that first-passage time (FPT) statistics for a one-dimensional random walk provides a good fit to the polarity time scale (PTS) in the...
Article
Full-text available
Birds are endowed with a magnetic sense that allows them to detect Earth's magnetic field and to use it for orientation. Physiological and behavioral experiments have shown the upper beak to host a magnetoreceptor. Putative magnetoreceptive structures in the beak are nerve terminals that each contain a dozen or so of micrometer-sized clusters of su...
Article
Coagulation of particles into aggregates during their settling in an aqueous solution is numerically simulated with regard to Brownian motion, Van der Waals and Stokes's forces, gravitation, and magnetostatic interactions. Clusters obtained have a fractal structure with the average fractal dimension d = 1.83. Magnetic grains do not group until thei...
Article
Single magnetic nanodots, exchange coupled to an antiferromagnetic (AF) matrix, can produce large exchange bias, while superparamagnetic behavior of the nanodots is suppressed. The exchange bias originates from the formation of a (quasi)spherical domain wall inside the AF matrix when the particle moment rotates under the influence of an external ma...
Article
Lamellar magnetism is a type of magnetic remanence, carried by uncompensated magnetic moments in monolayers at interfaces between nanoscale exsolution structures of antiferromagnetic hematite and paramagnetic ilmenite. Lamellar remanence is commonly found in rocks which have a very low susceptibility, implying a low concentration of magnetic oxides...
Article
The influence of collisions between the clusters of a precipitating material on its magnetization at the precipitation stage in an aqueous medium is analyzed. In laboratory experiments, when the sedimentation rate exceeds the value of this rate under natural conditions by several orders of magnitude, collisions are an important factor which sharply...
Article
Full-text available
Samples were obtained from three baked contacts and one lava flow along the upper Turonian-lower Coniacian Tovuz section, two baked contacts along the upper Coniacian-lower Santonian Paravakar section in the northern part of Armenia, and three baked contacts along the Titonian-Valanginian Kafan section in southern Armenia. A total of 130 samples we...
Article
Results of palaeointensity and palaeomagnetic studies for the volcanic rocks of 1450 Ma, from Early Riphaean Baltic shield dyke complex sampled in Lake Ladoga region (Karelia, Northwestern Russia) are reported. Electron microscope observations, thermomagnetic and hysteresis measurements indicate the presence of single domain (SD) to pseudo-single d...
Article
Coagulation of particles into aggregates during their deposition in a reservoir is numerically simulated with regard for Brownian motion, Van der Waals forces, gravitation, Stokes friction, and magnetostatic interaction, and the effect of this process on the depositional magnetization (DRM) is estimated. Clusters obtained due to random aggregation...
Article
A large volume of data on the paleointensity H an obtained by A.S. Bol’shakov and G.M. Solodovnikov is ignored in modern reconstructions because the authors did not indicate whether they used the check-point procedure for the detection of chemical alterations in rocks associated with determination of H an. The paper presents new values of H an dete...
Article
Large and stable negative magnetic anomalies in southwestern Sweden, southern Norway, the Adirondacks, USA, and Quebec, Canada, are related to rock units with a magnetic fraction consisting primarily of ilmeno-hematite or hemo-ilmenite. It has been suggested that the unusual magnetic stability of these rocks results from lamellar magnetism. This is...
Article
A representative collection of Upper Cretaceous rocks of Georgia (530 samples from 24 sites) is used for the study of magnetic properties of the rocks and the determination of the paleodirection and paleointensity (H an) of the geomagnetic field. Titanomagnetites with Curie points of 200–350°C are shown to be carriers of natural remanent magnetizat...
Article
Low-temperature demagnetization (LTD) experiments with TRMs and pTRMs using liquid nitrogen were carried out on samples with different (MD and PSD) domain structures to infer and to compare the type of domain structure of samples before and after LTD judged by the thermomagnetic criterion. This is based on testing materials against Thellier's law o...
Article
We report results of a collaborative investigation of the experimental properties of chemical remanent magnetization (CRM) acquired when nearly single-domain size magnetite undergoes low-temperature oxidation to maghemite and of viscous remanent magnetization (VRM) acquired by the daughter phase maghemite. Magnetite grains 100–200 nm in diameter we...
Article
Theoretical and experimental study of shape of the Arai-Nagata diagrams for the natural remanent magnetization (NRM) consisting of two low- and high-temperature partial thermal remanent magnetization vectors directed at angle $\theta$ to each other is considered. Assuming that the NRM is carried by single-domain and/or small pseudosingle-domain gra...
Article
The extreme scarcity of data on the behavior of the paleointensity H an in the geological past from rocks older than 400 Ma significantly hinders the development of our ideas of the geomagnetic field evolution and the geological history of the Earth as a planet. This work presents H an determinations for the Early Proterozoic using the Thellier met...
Article
Full-text available
Petromagnetic studies of a representative spinel peridotite collection from a number of localities along slowly spreading mid-ocean ridges were performed. It was established that oceanic peridotites usually contain two or more generations of ferrimagnetics formed in assemblages with metamorphic silicates at different temperatures. The crystallizati...
Article
The territory of Karelia (Baltic Shield) is virtually not represented in the global paleomagnetic database for the Lower Riphean time interval (1650—1350 Ma). As regards the paleointensity H an, the huge interval 1–2 Ga in length is represented in the global paleointensity database by only eight determinations concentrated in the interval 1–1.35 Ga...
Article
The global database on the paleointensity, containing determinations of the virtual dipole moment (VDM) for a stable (normal) regime of the geomagnetic field in a time interval of up to 3.5 Ga, is supplemented by new VDM determinations and analyzed. The field generation process started no later than 3–3.5 Ga (earlier data are absent) at the stage o...
Article
The paleointensity Han is determined from samples of Siberian traps collected in the Norilsk region and in the Bolshaya Nirunda River basin and dated at the Permian-Triassic boundary and the Lower Triassic (ages of 251-260 Ma). A Kazakhstan collection of basaltic andesites from two sections belonging to the Ural-Mongolian foldbelt and associated wi...
Article
Magnetic grain-size and coercivity distributions of a superparamagnetic (SP) particle ensemble together determine its frequency dependence of susceptibility (FDS). Investigating the mathematical theory of this dependence leads to a general dispersion relation between real and imaginary parts of the complex susceptibility for SP particle ensembles,...
Article
Clusters of superparamagnetic (SP) magnetite crystals have recently been identified in free nerve endings in the upper-beak skin of homing pigeons and are interpreted as being part of a putative magnetoreceptor system. Motivated by these findings, we developed a physical model that accurately predicts the dynamics of interacting SP clusters in a ma...
Article
A range of basaltic samples from Olby (France) and Vogelsberg (Germany) displaying the phenomenon of partial and complete self-reversal was studied in order to decipher the physical mechanism responsible for self-reversed magnetic remanence in basalts. Microscopic observations and rock magnetic measurements show titanomagnetite to be the carrier of...
Article
The exchange interaction at the boundary of coherently adjacent magnetic phases can be realized as the exchange anisotropy (EA) and, theoretically, can lead to a self-reversal of thermal remanent magnetization (TRM). A bias in the hysteresis loop (HL) can serve as a criterion indicating the presence of the EA. Results of numerical 3-D modeling of H...
Article
We report on the magnetic properties and the acquisition of a chemical remanent magnetization (CRM) in a field of 100 μT as a function of temperature and time during the lepidocrocite–maghemite–haematite reaction chain. The development of CRM was monitored at a series of 13 temperatures ranging from 175 to 550 °C; data acquisition was done at the s...
Article
Magnetic beads and superparamagnetic (SP) colloid particles have successfully been employed for micromechanical manipulation of soft material, in situ probing of elastic properties, and design of smart materials (ferrogels). Here we derive analytical expressions for the equilibrium shape of magnetic fibers, considering two end-member cases, (a) SP...
Article
Repeated heating and cooling cycles appear frequently in thermomagnetic experiments used to infer the palaeomagnetic field intensity. According to the fundamental assumptions used to interpret these measurements, a remanence acquired at some temperature T is not influenced by subsequent heating and cooling cycles at lower temperatures. This presump...
Article
A rigorous theory of biased hysteresis loops in ferro-antiferromagnetic bilayers in the presence of exchange coupling at their boundary is constructed under the assumption of one-dimensional variation in the direction of the spontaneous magnetization vector. Loop characteristics are comprehensively studied in the case of a spatially extended antife...
Article
The shifted hysteresis loops (SHL) are usually referred to the exchange anisotropy resulting from superexchange interaction across the interface of a two-phase ferrimagnetic (FM) - antiferrimagnetic (AF) system like maghemite-hematite or ordered-disordered hemoilmenite intergrowths. The three-dimensional numerical micromagnetic modeling including t...
Article
Full-text available
Petrographic and petromagnetic studies of a representative collection of peridotites from various localities on the Mid-Atlantic Ridge have been carried out. It is shown that secondary magnetization of peridotites comes into being usually prior to the onset of serpentinization, in the course of the preceding medium-temperature metamorphic recrystal...
Article
A collection of 17 natural and two artificial samples containing grains with different domain structures (single-domain (SD), pseudosingle-domain (PSD), and multidomain (MD)) was used for experimental modeling of stepped thermal demagnetization with the aim of recognizing possible errors in paleodirection determinations. A two- or multicomponent th...
Article
The evolution of the virtual dipole moment (VDM) over the last 400 Myr is analyzed on the basis of paleointensity determinations selected from the IAGA Paleointensity Database and supplemented by new data. The χ2-test confirmed, on a 90% significance level, the hypothesis of a bimodal paleointensity distribution resulting from the superposition of...
Article
Theoretical calculations of hysteresis loops in exchange coupled maghemite-hematite or ordered-disordered hemoilmenite bilayers, based on analytical micromagnetic ap- proach, is carried out. If the exchange coupling is compatible with those of the antifer- romagnetic (AF) layer and the layer is thicker than the domain wall (DW) width, the DW forms...
Article
We report an experimental and theoretical study of non-linear Arai–Nagata diagrams for samples containing pseudo-single-domain (PSD) and multidomain (MD) magnetite. Our aim is to reveal the physical reasons for the deviation of these plots from ideal straight lines. Contrary to expectations, the concavity of the Arai–Nagata diagrams is not related...
Article
New magnetic and mineralogical findings on self-reversing hemoilmenite (Fe2−y TiyO3) grains from Pinatubo lavas (1991 eruption) provide important clues regarding the acquisition process of reverse thermoremanent magnetization (rTRM) in this solid solution series. Magnetic force microscopy indicates the presence of multidomain magnetic structures in...
Article
The apparent successful application of the Thellier’s method of paleointensity or paleofield direction determinations on multi-domain (MD) and pseudo-single-domain (PSD) grains suggests the validity of the Thellier’s laws of independence and additivity of partial thermoremanent magnetizations (pTRMs). However, it is well known that these laws are v...
Article
The domain structure in submicron grains of magnetite is mainly determined by their size (d) and, to a lesser degree, by their geometry. Only a uniform single-domain structure exists at d ≤ 50 nm. In cubic magnetite particles, at least two modes coexist at d = 55.5-110 nm: a pseudo-single-domain "flower" mode and a "curling" mode. The upper limit o...
Article
Correct determination of paleointensity and paleotectonic and magnetostratigraphic reconstructions from ingneous rocks are possible only in the case of validity of the Thellier laws on the pTRM independence and additivity, which hold rigorously only in samples with a single-domain grain size. The Bolshakov-Shcherbakova thermomagnetic criterion (TC)...
Article
The magnetic susceptibility was numerically estimated from the Boltzmann statistics applied to an ensemble of small number (2 to 20) of single-domain (SD) particles with the volume concentration c ranging from c → 0 (no interaction) to 5%. It is shown that the magnetostatic interaction virtually has no effect on the equilibrium value of the suscept...
Article
An experimental study was carried out to investigate the thermal demagnetization properties of partial thermoremanent magnetization (pTRM). Fifteen different igneous rocks and five synthetic specimens containing crushed and hydrothermally grown magnetite of different grain sizes were studied. The domain structures (DS) of the samples cover the rang...
Article
Full-text available
Homing pigeons and migratory birds are well known examples for animals that use the geomagnetic field for their orientation. Yet, neither the underlying receptor mechanism nor the magnetoreceptor itself is known. Recently, an innervated structure containing clusters of magnetite nanocrystals was identified in the upper beak skin of the homing pigeo...
Article
Energy estimates derived for normal magnetization of ferromagnets in rocks from the zero (WZS) and absolute zero states (WAZS) and for their remagnetization from the magnetic saturation state are obtained. Experimental data and theoretical estimates are compared, and the parameter NT is found to correlate well with the ratio WAZS/WZS. The inferred...
Article
The formation processes of thermoremanent (TRM) and crystallization (CRM) magnetizations in an ensemble of interacting single-domain grains are numerically modeled using the Monte Carlo method to account for thermal fluctuations. The numerical results show that TRM > CRM at the volume concentration of a ferromagnet c ≤ 1-3% (weak interaction), and...
Article
Full-text available
Electron micrographs of magnetotactic bacteria reveal that chains of magnetosomes are often bent. This is surprising inasmuch as straight chains are actually the most favourable arrangement for magnetonavigation achieving the maximum value of the bacterial net magnetic moment. In order to answer the question of what causes the chains to bend, we ca...