The initial magnetic susceptibility of polydisperse ferrofluids: A comparison between experiment and theory over a wide range of concentration

2016 ◽  
Vol 145 (8) ◽  
pp. 084909 ◽  
Author(s):  
Anna Y. Solovyova ◽  
Olga A. Goldina ◽  
Alexey O. Ivanov ◽  
Aleksandr V. Lebedev ◽  
Ekaterina A. Elfimova
Keyword(s):  
Magnetic Susceptibility ◽  
Wide Range ◽  
Initial Magnetic Susceptibility

Suppression of Ferromagnetism in EuxCa1-xB6

2012 ◽  
Vol 190 ◽  
pp. 97-100 ◽  
Author(s):  
V.V. Glushkov ◽  
A.V. Kuznetsov ◽  
I. Sannikov ◽  
A.V. Bogach ◽  
S.V. Demishev ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Curie Temperature ◽  
Single Crystals ◽  
Effective Magnetic Moment ◽  
Paramagnetic State ◽  
Low Field ◽  
Wide Range ◽  
Free Ion ◽  
The Eu

We report the magnetic properties of EuxCa1-xB6 single crystals (0.756x1) studied in the wide range of temperatures (1.8-300 K) and magnetic fields (up to 50 kOe). It was found that low field magnetic susceptibility χ (T) follows the Curie-Weiss law χ~(T-Θp)-1 at high temperatures for all the concentrations studied. The effective magnetic moment of the Eu2+ ion estimated from the data diminishes from the free ion value μeff7.93μB (μB - Bohr magneton) for x=1 to μeff7.3μB for x=0.756. A universal behavior of magnetic susceptibility χ~(T-Θ)-α (α=1.5) is detected close to the Curie temperature TC in the paramagnetic state at both metallic (x>xC~0.8) and dielectric (xC.

A.C. initial magnetic susceptibility and spin reorientation transitions in (ErxR1−x)2Fe14B magnets (R=Nd and Dy)

1989 ◽  
Vol 69 (2) ◽  
pp. 131-136 ◽  
Author(s):  
M.R. Ibarra ◽  
C. Marquina ◽  
P.A. Algarabel ◽  
J.I. Arnaudas ◽  
A. del Moral
Keyword(s):  
Magnetic Susceptibility ◽  
Spin Reorientation ◽  
Initial Magnetic Susceptibility

A Discussion on natural strain and geological structure - Strain and anisotropy in rocks

1976 ◽  
Vol 283 (1312) ◽  
pp. 27-42 ◽  
Keyword(s):  
Magnetic Susceptibility ◽  
Shear Wave ◽  
Finite Strain ◽  
Preferred Orientation ◽  
Seismic Velocities ◽  
Magnetic Susceptibility Anisotropy ◽  
Wave Velocities ◽  
Natural Strain ◽  
Shear Wave Velocities ◽  
Wide Range

The evaluation of finite strain in naturally deformed rocks is restricted by the limited occurrence of good natural strain indicators which are also homogeneous with respect to the matrix. This problem is overcome by establishing the relation between measured finite strain and those physical behaviour characteristics of rocks that are dependent upon the anisotropy resulting from deformation. Accordingly, the strain measured from natural indicators is calibrated against ( degree of preferred orientation, (b) magnetic susceptibility anisotropy, and (r) seismic anisotropy. This _ will permit three approaches to be used independently for the evaluation of strain, provided that a minimal number of actual strains are available. The relation between measured strain and the degree of preferred orientation of layer silicates as revealed by X-ray transmission goniometry is established for a group of fine grained tectonites of dominantly planar fabric which have an average deformation ellipsoid of form 1.6:1 :,0.26. The strains measured from the degree of preferred orientation are in remarkable agreement with those measured from natural strain indicators. The measured deformation ellipsoids for a wide range of strains are also compared to the correlative ellipsoids of magnetic susceptibility anisotropy. The axes of both sets of ellipsoids are coincidental and the shape relationship between deformation and magnetic susceptibility ellipsoids is established by linear regression. Finally, the anisotropy of seismic velocities is determined by measuring the pseudocompressional velocity and two orthogonally polarized pseudo shear wave velocities for each of a minimum of nine non-coplanar directions. The velocity surfaces thus obtained define an elastic or seismic velocity anisotropy ellipsoid, the axes of which are also precisely coincidental with those of the finite deformation ellipsoid. The influence of rock fabric upon seismic velocities is such that for a rock which has undergone a principal finite extension of 135 % and a finite shortening of 65 %, the difference of compressional and shear wave velocities between these two directions is in the ratio 1.26:1 for P waves and 1.33:1 for S waves.

scholarly journals Iron-containing phases in metallurgical and coke dusts as well as in bog iron ore

Nukleonika ◽  
2017 ◽  
Vol 62 (2) ◽  
pp. 187-195 ◽  
Author(s):  
Tadeusz Szumiata ◽  
Marzena Rachwał ◽  
Tadeusz Magiera ◽  
Katarzyna Brzózka ◽  
Małgorzata Gzik-Szumiata ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Spinel Structure ◽  
Iron Ore ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mineral Phases ◽  
Coke Plants ◽  
Wide Range ◽  
Specific Magnetic Susceptibility ◽  
Diffraction Patterns

Abstract Several samples of dusts from steel and coke plants (collected mostly with electro filters) were subjected to the investigation of content of mineral phases in their particles. Additionally, sample of bog iron ore and metallurgical slurry was studied. Next, the magnetic susceptibility of all the samples was determined, and investigations of iron-containing phases were performed using transmission Mössbauer spectrometry. The values of mass-specific magnetic susceptibility χ varied in a wide range: from 59 to above 7000 × 10−8 m-3·kg−1. The low values are determined for bog iron ore, metallurgical slurry, and coke dusts. The extremely high χ was obtained for metallurgical dusts. The Mössbauer spectra and X-ray diffraction patterns point to the presence of the following phases containing iron: hematite and oxidized magnetite (in coke and metallurgical dusts as well as metallurgical slurry), traces of magnetite fine grains fraction (in metallurgical dusts), amorphous glassy silicates with paramagnetic Fe3+ and Fe2+ ions, traces of pyrrhotite (in coke dusts), α-Fe and nonstoichiometric wüstite (in metallurgical slurry), as well as ferrihydrite nanoparticles (in bog iron ore). For individual samples of metallurgical dusts, the relative contributions of Fe2+/3+ ions in octahedral B sites and Fe2+ ions in tetrahedral A sites in magnetite spinel structure differs considerably.

New Magnetoresistance Results in GdB6

2012 ◽  
Vol 190 ◽  
pp. 77-80 ◽  
Author(s):  
M.A. Anisimov ◽  
A.V. Bogach ◽  
V.V. Glushkov ◽  
S.V. Demishev ◽  
N.A. Samarin ◽  
...  
Keyword(s):  
Experimental Data ◽  
Magnetic Susceptibility ◽  
Low Temperature ◽  
Spin Polarization ◽  
Complex Behavior ◽  
Negative Component ◽  
High Quality ◽  
Wide Range ◽  
Linear And Nonlinear ◽  
Local Spin Polarization

Detailed study of transverse magnetoresistance (MR) and magnetic susceptibility have been done on the high quality single crystals of antiferromagnet GdB6 (TN15.5K) in the wide range of temperatures 2-40K in magnetic fields up to 8T. The data obtained allow to establish the low temperature antiferromagnetic (AFMII) phase below T*~4.7K with the complex behavior of MR including the field hysteresis of the magnetoresistance. It was shown that MR behavior depends on the cooling-warming prehistory in AFM state of GdB6. The analysis of experimental data allowed us to deduce three contributions to MR in AFM(I), (T*) and paramagnetic (PM) phases of GdB6. In addition to the main negative component Δρ˿ρ~ H2 interpreted in terms of Yosida model both the linear and nonlinear magnetic contributions were also established. The anomalies of MR found in AFM(I) state seem to be associated with the local spin polarization of 5d-electron states of Gd3+ ion.

scholarly journals A method of measuring magnetic susceptibilities

1931 ◽  
Vol 132 (820) ◽  
pp. 442-459 ◽  
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Torsion Balance ◽  
The Body ◽  
Small Element ◽  
Uniform Field ◽  
Magnetic Susceptibilities ◽  
Wide Range ◽  
Faraday Method ◽  
The Magnetic Field

Among the different methods which can be used to measure the magnetic susceptibility of feebly magnetic substances, the most practical, and those most frequently employed at the present time, depend essentially on the measurement of the force acting on the substance when placed in a non-uniform field. This force is given by the well-known formula F x = χ ∫ v 0 H d H/d x d V, where χ is the volume susceptibility, (H) is the magnetic field, d H/ d x is the gradient of the magnetic field in the direction x in which the force is measured at the site of a small element of volume ( d V). Corresponding to the wide range of susceptibility, and to the different physical states and conditions which occur, a number of methods of measuring this force have been developed. In all these methods, since they are based on the measurement of the force on the substance, and since it is by the displacement of the body that the force is measured, it is essential that the body should be movable. The force acting on the body is small, usually only a few dynes, and delicate methods have to be used for making the measurements, as, for instance, in the Curie-Faraday method where the substance is carried on a sensitive torsion balance.

scholarly journals Investigation of polluted alluvial soils by magnetic susceptibility methods: a case study of the Litavka River

2013 ◽  
Vol 8 (No. 4) ◽  
pp. 151-157 ◽  
Author(s):  
Š. Dlouhá ◽  
E. Petrovský ◽  
A. Kapička ◽  
L. Borůvka ◽  
Ch. Ash ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Soil Layer ◽  
Soil Conditions ◽  
Natural Soil ◽  
Alluvial Soils ◽  
Risk Elements ◽  
Anthropogenic Origin ◽  
Increased Risk ◽  
Wide Range

Serious pollution of alluvial soils by a wide range of potentially toxic elements is usually observed in the valleys with mining and metallurgical industry. To outline areas of increased risk elements inputs, measurements of soil magnetic susceptibility can be used. This method is based on the measurement of the concentration of ferrimagnetic minerals of anthropogenic origin, mainly iron oxides, which are closely associated with risk elements such as heavy metals. The aim of this study is to examine the link between magnetic susceptibility of poorly drained Litavka River alluvial soils located in the mining/smelting region of Příbram (Czech Republic) and the observed high concentration of risk elements in soils. Surface volume magnetic susceptibility and the vertical distribution of magnetic susceptibility in soil profiles were measured in situ. On the basis of field measurements, selected parts of soil cores were sampled for a detailed magnetic and chemical analysis. Our results demonstrate a statistically significant correlation between magnetic susceptibility and soil concentration of Cu, Pb, and Zn. The magnetically enhanced soil layer, relatively low frequency-dependent susceptibility, presence of Verwey transition, and scanning electron microscope observations suggested a prevalence of coarse magnetite/maghemite, likely of anthropogenic origin. However, the magnetic properties in-situ also reflected the natural soil conditions and soil processes. The high content of organic matter, varying reductive/oxidative condition, and vertical migration of magnetic phases were the main factors influencing the observed magnetic susceptibility values.

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