scholarly journals Introduction of thermal activation in forward modeling of hysteresis loops for single-domain magnetic particles and implications for the interpretation of the Day diagram

2003 ◽  
Vol 108 (B3) ◽  
Author(s):  
Luca Lanci ◽  
Dennis V. Kent
Keyword(s):  
Thermal Activation ◽  
Magnetic Particles ◽  
Hysteresis Loops ◽  
Forward Modeling ◽  
Single Domain

scholarly journals Integrated Magnetic Analyses for the Discrimination of Urban and Industrial Dusts

Minerals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1056
Author(s):  
Beata Górka-Kostrubiec ◽  
Tadeusz Magiera ◽  
Katarzyna Dudzisz ◽  
Sylwia Dytłow ◽  
Małgorzata Wawer ◽  
...  
Keyword(s):  
Grain Size ◽  
Magnetic Particles ◽  
Steel Production ◽  
Hysteresis Loops ◽  
Street Dust ◽  
Single Domain ◽  
Magnetic Fraction ◽  
Magnetic Methods ◽  
Urban Dusts ◽  
Traffic Related Pollution

Industrial and urban dusts were characterized by investigating their magnetic properties. Topsoil composed of technogenic magnetic particles (TMP) originating from areas affected by three ironworks, street dust mainly composed of traffic-related pollution, and particulate matter (PM) from urban agglomeration in Warsaw, Poland were investigated. Several magnetic methods, namely magnetic susceptibility, thermomagnetic curves, hysteresis loops, decomposition of isothermal remanent magnetization acquisition curves, and first-order reversal curves, were performed to evaluate the magnetic fraction of dust. Magnetite was the main magnetic phase in all types of samples, with a small amount of high-coercive hematite within ironworks and street dust samples. Significant differences were observed in the domain structure (grain size) of industrial and traffic-related magnetic particles. The grain size of TMP obtained from steel production was in the range of 5–20 µm and was predominated by a mixture of single-domain (SD) and multidomain (MD) grains, with the prevalence of SD grains in the topsoil affected by Třinec ironwork. The traffic-related dust contained finer grains with a size of about 0.1 µm, which is characteristic of the pseudo-single-domain (PSD)/SD threshold. Street dusts were composed of a slightly higher proportion of MD grains, while PM also revealed the typical behavior of superparamagnetic particles.

Single-domain theory for the reversible effect of small uniaxial stress upon the remanent magnetization of rock

1977 ◽  
Vol 14 (9) ◽  
pp. 2047-2061 ◽  
Author(s):  
J. P. Hodych
Keyword(s):  
Remanent Magnetization ◽  
Thermal Activation ◽  
Magnetocrystalline Anisotropy ◽  
Uniaxial Stress ◽  
Titanium Content ◽  
Single Domain ◽  
Stress Axis ◽  
Compression Axis ◽  
Saturation Remanence ◽  
Approximate Expressions

This paper on small uniaxial stress changing the remanent magnetization of rock is a companion to my previous paper on stress changing susceptibility, both phenomena being of current interest in attempts at earthquake forecasting.Theoretical expressions are derived (using rigorous energy-minimization but ignoring thermal activation) for reversible change in remanence parallel to the stress axis for samples containing single-domain grains of a ferromagnet with cubic magnetocrystalline anisotropy (K1 positive or negative) and anisotropic magnetostriction. The grains are assumed to be non-interacting and randomly oriented spheres or ellipsoids of revolution elongated along [Formula: see text], [Formula: see text], or [Formula: see text]. Also, approximate expressions are given for samples containing multidomain grains with very strongly pinned walls. Thermal (or chemical), anhysteretic, and saturation remanence are discussed.For remanence change perpendicular to the stress axis, one expects −1/2 the above expressions for change parallel to the stress axis, which is easily proven for thermal remanence.The expressions predict that for magnetite-bearing rock the decrease in thermal remanence along a 100 bar (1 × 104 kPa) compression axis should be 0.76% for spherical single-domain grains, 0.27% for 1.4 to 1 elongation along [Formula: see text], and 0.09% for great elongation along [Formula: see text]. The decrease for equidimensional multidomain grains with strongly-pinned walls should be ~0.38%. These are all much smaller than the corresponding estimates for susceptibility, but both remanence and susceptibility decreases should become larger and more comparable as titanium content increases.

Noncollinear states in a chain of single-domain magnetic particles

JETP Letters ◽  
2011 ◽  
Vol 93 (12) ◽  
pp. 716-719 ◽  
Author(s):  
K. P. Mukhamatchin ◽  
A. A. Fraerman
Keyword(s):  
Magnetic Particles ◽  
Single Domain ◽  
A Chain

Construction of hysteresis loops of single domain elements and coupled permalloy ring arrays by magnetic force microscopy

2003 ◽  
Vol 93 (10) ◽  
pp. 8540-8542 ◽  
Author(s):  
Xiaobin Zhu ◽  
P. Grütter ◽  
V. Metlushko ◽  
Y. Hao ◽  
F. J. Castaño ◽  
...  
Keyword(s):  
Magnetic Force Microscopy ◽  
Magnetic Force ◽  
Hysteresis Loops ◽  
Single Domain ◽  
Force Microscopy
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