Temperature dependence of the magnetic properties of reservoir rocks and minerals and implications for in situ borehole predictions of petrophysical parameters

Geophysics ◽  
2012 ◽  
Vol 77 (3) ◽  
pp. WA211-WA221 ◽  
Author(s):  
Arfan Ali ◽  
David K. Potter
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Temperature Dependence ◽  
High Field ◽  
Magnetic Measurements ◽  
Clay Content ◽  
Petrophysical Parameters ◽  
Reservoir Rocks ◽  
Fluid Permeability

Recent work has shown strong correlations between magnetic susceptibility and key petrophysical parameters such as clay content and fluid permeability. The magnetic measurements in previous work were mainly undertaken at ambient (room temperature) conditions on core samples. The present study involved theoretical modeling and experimentation on the temperature dependence of the magnetic properties (mass magnetization and magnetic susceptibility) of reservoir rocks and minerals over a range of low and high applied fields. It paves the way for correctly interpreting borehole magnetic susceptibility measurements, and accurately predicting petrophysical properties in situ, from a potentially new suite of low and high field borehole magnetic tools. The temperature dependent magnetic susceptibility measurements provide an improved means of quantifying the diamagnetic versus paramagnetic mineral content in reservoir rocks compared to a single ambient measurement. Paramagnetic clays, such as illite, are important in controlling the fluid permeability in many of these samples, and we again saw correlations between the magnetic measurements, paramagnetic clay content, and permeability. We also show how to derive ferrimagnetic mineral hysteresis curves by subtracting the high field magnetic data from the total signal. The resulting magnetic hysteresis curves give important information concerning the content (often only a few ppm, which X-ray diffraction cannot detect), mineralogy, and domain state of the ferrimagnetic particles.

scholarly journals Structural and Magnetic Properties of Ni0.8Fe0.2/Ti Nanoscale Multilayers

Nanomaterials ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 780 ◽  
Author(s):  
Ricardo López Antón ◽  
Juan A. González ◽  
Juan P. Andrés ◽  
Andrei V. Svalov ◽  
Galina V. Kurlyandskaya
Keyword(s):  
Magnetic Properties ◽  
Temperature Dependence ◽  
Layered Structure ◽  
Magnetic Measurements ◽  
Hysteresis Loops ◽  
Multilayered Structures ◽  
X Ray ◽  
Structural And Magnetic Properties

The influence of the thickness of the Ni0.8Fe0.2 (Permalloy, Py) layers on the structural and magnetic properties of magnetron sputtered Py/Ti multilayers was studied. The thickness of the Py layers was varied in the interval of 8 to 30 Å. X-ray reflectivity scans evidence the existence of a well-defined layered structure in all the samples considered, but also the presence of a complex intermixed interface. The shape of both the temperature dependence of magnetization and the hysteresis loops of the multilayered structures depends strongly on Py thickness. Magnetic and reflectivity measurements were comparatively analyzed in order to better understand the structure of the samples, and specifically, their interfaces. In particular, the presence of small superparamagnetic Py at the interfaces of the samples, especially evident in the samples with the thinnest Py layers, seems confirmed by the magnetic measurements, agreeing well with the reflectivity results.

High Temperature and High Pressure Synthesis and Magnetic Properties of Arsenic-Based Filled Skutterudite Compounds

2019 ◽  
Vol 289 ◽  
pp. 85-92
Author(s):  
Chihiro Sekine ◽  
Toshihide Osanai ◽  
Hariharan Ponmani ◽  
Atachariya Phuangyod ◽  
Yukihiro Kawamura ◽  
...  
Keyword(s):  
High Pressure ◽  
Magnetic Properties ◽  
Electrical Resistivity ◽  
Magnetic Susceptibility ◽  
Magnetic Measurements ◽  
Spin Fluctuations ◽  
Filled Skutterudite ◽  
Lattice Constants ◽  
Pressure Synthesis ◽  
New Superconductor

We have succeeded in synthesizing new arsenic-based filled skutterudite compounds CaFe4As12and BaOs4As12under high pressure. These compounds have lattice constants of 8.3288 and 8.5809 Å, respectively. The magnetic properties of CaFe4As12and BaOs4As12have been studied by means of electrical resistivity, magnetic susceptibility and magnetization measurements. The electrical resistivity and magnetic measurements indicate that CaFe4As12is a nearly ferromagnetic metal with spin fluctuations of Fe 3delectrons and BaOs4As12is a new superconductor with a transition temperature around 3 K.

scholarly journals Magnetic Susceptibility of Soils from Eastern Botswana: A Reconnaissance Survey and Potential Applications

2015 ◽  
Vol 7 (4) ◽  
pp. 45 ◽  
Author(s):  
Rubeni Tawanda Ranganai ◽  
Moikwathai Moidaki ◽  
James G. King
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Land Use Planning ◽  
Magnetic Measurements ◽  
Parent Material ◽  
Appreciable Amount ◽  
Frequency Dependent ◽  
Magnetic Susceptibilities ◽  
Basement Rocks ◽  
Rock And Soil

<p class="zhengwen">Soil magnetic properties measurements are relatively fast and inexpensive but have been proved to be sufficient for preliminary investigations in diverse socio-developmental issues. This paper presents results of a reconnaissance study of soil colour and magnetic susceptibility (c) in eastern Botswana, where ~80% of the population resides. The work is a first step to creating a database of rock and soil magnetic properties and to document spatial variations in magnetic properties in the country. These measurements are important as constraints for interpretation of available aeromagnetic data and can also be exploited for environmental soil research (pollution) and land-use planning (agriculture). The soils sampled include derivatives of varying types and provenance such as Archean gneissic granitoids, metamorphosed rocks (granulites), volcano-sedimentary assemblages, Karoo basalts, and alluvial sediments. A soil colour chart was used since soil colours and magnetic properties are diagnostic of its parent rock sources and weathering profiles. Soil magnetic susceptibilities were measured at both low frequency (0.46 MHz, clf) and high frequency (4.6 MHz, chf), thus allowing calculation of frequency-dependent susceptibility (cfd, cfd%) for detecting ultra-fine ferromagnetic minerals.</p>It was found that soils with Hues ranging from 7.5YR to 10YR have appreciable amount of magnetic materials and soils with Hues of 2.5YR are generally nonmagnetic. The results of soil magnetic susceptibility profiles show spatial variation closely related to the variation in basement rocks, which provides excellent evidence that the magnetic susceptibility variation reflects basement rocks or bedrock composition (soil parent material). In relation to the Botswana physiographic units, soils from the hardveld (Precambrian) show the highest susceptibilities, followed by those from the sandveld, with the lowest values being from the alluvial. The frequency dependent magnetic susceptibilities indicate the presence of ultra-fine super-paramagnetic minerals such as magnetite/maghemite. It is suggested that a systematic and continuous programme of rock and soil magnetic measurements would benefit various socio-economic and development priority sectors of Botswana. This also applies to many developing countries in Africa where soil physics and measurement of soil susceptibility in particular, is generally still at an embryonic stage.

Magnetische Eigenschaften von [Cu{OCH2CH2N(C4H9)2}NCO]4 im Bereich von 10 bis 240 K / Magnetic Properties of [Cu{OCH2CH2N(C4H9)2}NCO]4 in the Temperature Range from 10 to 240 K

1998 ◽  
Vol 53 (1) ◽  
pp. 58-62
Author(s):  
W. Münch ◽  
L. Walz ◽  
M. König
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Temperature Dependence ◽  
Title Compound ◽  
Temperature Range ◽  
New Phase ◽  
Exchange Parameters

The magnetic properties of the title compound were re-investigated, since a new phase below 240 K has recently been identified. The exchange parameters were evaluated from the temperature dependence of the magnetic susceptibility with a Heisenberg operator taking into account the high pseudo-symmetry of the tetrameric units observed.

ESR STUDIES OF GMR RELATED MATERIALS I: ESR of Mn IN LaMnO3 AND La0.99Ca0.01MnO3

2000 ◽  
Vol 14 (25n26) ◽  
pp. 883-897 ◽  
Author(s):  
N. ARAI ◽  
K. SUGAWARA
Keyword(s):  
Magnetic Susceptibility ◽  
Temperature Dependence ◽  
Spin System ◽  
High Field ◽  
Energy Gap ◽  
Low Field ◽  
High Field Esr ◽  
Clear Signal ◽  
Spin Clusters ◽  
G Value

ESR measurements are carried out for La 1-x Ca x MnO 3 (x=0, 0.01) from 760 K down to 4 K. A clear signal was observed above 260 K, presumably arising from Mn 3+ and Mn 4+, but two kinds of signals, the low-field and high-field ESR with g≃2, were observed below it. The high- and low-field signals are tentatively assumed to originate from Mn 4+ and Mn 3+, respectively. The g-value, linewidth, and intensity of the high-field signal nearly follow ∝1/(T-106). The temperature dependence of g-shift of the low-field signal is similar to that of magnetic susceptibility of LaMnO 3. The ESR intensity anomalously increases at temperatures between about 150 K and 250 K, which is tentatively ascribed to the occurrence of "spin-clusters". Above ≃300 K, the ESR intensity nearly follows Curie's law, and the linewidth is proportional to exp (-500/T), an indication of some kind of energy-gap existence in the Mn spin system.

MAGNETIC SUSCEPTIBILITY OF YRh2

1993 ◽  
Vol 07 (01n03) ◽  
pp. 834-837
Author(s):  
H. YAMADA ◽  
W. STEINER
Keyword(s):  
Magnetic Susceptibility ◽  
Temperature Dependence ◽  
Density Of States ◽  
Phase Structure ◽  
Magnetic Measurements ◽  
Tight Binding ◽  
The Other ◽  
Spin Fluctuations ◽  
Tight Binding Method ◽  
Good Agreement

Magnetic measurements for YRh2 with the cubic Laves phase structure were performed between 4.2 and 600 K. It was observed that the susceptibility shows a very weak temperature dependence and our data are about 40 % larger than the observed one by Loebich and Raub. On the other hand, the temperature dependence of the susceptibility was also estimated theoretically, by using the density-of-states curve calculated in the tight-binding method and by taking into account the effect of spin fluctuations. A good agreement between our observed and calculated results is obtained.

The magnetic properties of natural pigments: preliminary analyses for their identification in Fine Arts

2021 ◽  
Author(s):  
Chiara Anselmi ◽  
Antonio Sgamellotti ◽  
Manuela Vagnini ◽  
Aldo Winkler
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Magnetic Measurements ◽  
Rock Magnetism ◽  
Fine Arts ◽  
Magnetic Behavior ◽  
Spectroscopic Techniques ◽  
Magnetic Carriers ◽  
Magnetic Techniques ◽  
Synthetic Pigments

&lt;p&gt;A multidisciplinary approach, including compositional, spectroscopic and microscopic methodologies, is often used for the analysis and identification of pigments in Fine Arts. Although a large part of widely used natural and synthetic pigments contain Fe-oxides and hydroxides, their magnetic characterization is still poorly explored. The application of rock magnetism analyses through fast, cheap and non-destructive measurements, can be instead useful for the identification and discrimination of pigments through their distinctive magnetic properties.&lt;/p&gt;&lt;p&gt;In this preliminary study, the magnetic properties of several iron-based commercial pigments together with paintings models and supports, were analyzed.&lt;/p&gt;&lt;p&gt;In order to investigate the compositional differences of pigments by means of their magnetic behavior, the magnetic susceptibility, the hysteresis properties and the magnetic susceptibility variation at low and high temperature were measured on selected samples.&lt;/p&gt;&lt;p&gt;All the pigments showed different magnetic properties, mainly related to variable proportions of magnetite, hematite and maghemite as the main magnetic carriers.&lt;/p&gt;&lt;p&gt;Further studies will be addressed to define a protocol for applying the magnetic techniques to the characterization of pigments, including tests on samples produced by different brands and different periods, with the final aim of integrating the magnetic measurements with the different spectroscopic techniques commonly employed for the preservation and the analysis of cultural heritage.&lt;/p&gt;

The Magnetic Susceptibility of Southwestern Obsidian: An Exploratory Study

1997 ◽  
Vol 17 (4) ◽  
pp. 271-285 ◽  
Author(s):  
Tim Church ◽  
Carlos Caraveo
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Exploratory Study ◽  
Magnetic Measurements ◽  
Eastern Mediterranean ◽  
Volcanic Glass

The magnetic properties of volcanic glass and obsidian have long been known. Selected magnetic properties have proven useful discriminators among eastern Mediterranean obsidian sources. A recent exploratory study of the magnetic susceptibility of Southwestern obsidians indicates that it may prove a useful tool in this region also. Magnetic measurements of samples from many of the major obsidian sources in the Southwest were analyzed in an exploratory study of the technique and the resulting data are presented here. The technique and its limitations are also discussed.

scholarly journals Spectral, thermal and magnetic properties of Cu(II) and Ni(II) complexes with Schiff base ligands

2011 ◽  
Vol 76 (12) ◽  
pp. 1639-1648 ◽  
Author(s):  
Beata Cristóvão
Keyword(s):  
Thermal Analysis ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Schiff Base ◽  
Ir Spectroscopy ◽  
Magnetic Measurements ◽  
Magnetic Moments ◽  
Schiff Base Ligands

Mononuclear copper(II) and nickel(II) complexes of the formulae [Cu(L1)] (1), [Ni(L1)] (2), [Cu(L2)] (3) and [Cu(L3)H2O] (4) (where L1 = N,N?-ethylenebis(4,6-dimethoxysalicylidenaminato), L2 = N,N?-ethylenebis(5-bromosalicylidenaminato) and L3 = N,N?-ethylenebis(5-bromo-3-methoxysalicylidenaminato)) were synthesized as microcrystalline powders and characterized by IR spectroscopy, thermal analysis and magnetic measurements. The magnetic susceptibility of the Cu(II) complexes changed with temperature according to the Curie-Weiss law. The complexes 1, 3 and 4 exhibit magnetic moments of 2.29, 2.20 and 1.88 ?B, respectively, at 303 K. These values practically do not change with lowering the temperature to 77 K. The nickel(II) complex 2 is diamagnetic.

Magnetic properties of rare earth chromium borates at high temperatures

2021 ◽  
pp. 166-170
Author(s):  
O.K. Kuvandikov ◽  
◽  
N.I. Leonyuk ◽  
V.V. Malsev ◽  
M.M. Kuzmin ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Rare Earth ◽  
Temperature Dependence ◽  
High Temperatures ◽  
Wide Temperature Range ◽  
Magnetic Moments ◽  
Chemical Formula ◽  
Temperature Range ◽  
Curie Temperatures

Temperature dependence of the magnetic susceptibility has been studied for rare-earth borates NdCr3(BO3)4, SmCr3(BO3)4 and LuCr3(BO3)4 by the Faradey method in the wide temperature range (300-1200 K). The dependence for each phase follows the Curi - Weis law. The Curie temperatures, Neel temperatures and magnetic moments corresponding to the chemical formula of the crystals, have been found.

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