Hysteresis Loop Shifts in Magnetic Field Cooled FeOOH Nanoparticles

1999 ◽  
Vol 581 ◽  
Author(s):  
M.S. Seehra ◽  
Paromita Roy ◽  
A. Manivannan
Keyword(s):  
Magnetic Field ◽  
Hysteresis Loop ◽  
Spin Glass ◽  
Applied Magnetic Field ◽  
Magnetic Moment ◽  
Open Loop ◽  
Zero Field ◽  
Interparticle Interactions

ABSTRACTMeasurements of the magnetization M as a function of temperature (5K - 300K) and applied magnetic field H (up to 50 kOe) in 30 Å particles of FeOOH are reported. M increases with decreasing T, peaking at TB = 65 K below which the ZFC (zero-field-cooled) and the FC (field-cooled) data separate. Hysteresis loop measured at 10 K for ZFC shows an open loop up to 40 kOe with coercivity = 2 kOe. For the FC case, the loop shifts and the loop-shift increases with the cooling field ItL, approaching saturation above Hc = 20 kOe. From the variation of M vs H above TB, a magnetic moment/particle μp = 300 μB is determined. These results suggest that the FeOOH nanoparticles have an antiferromagnetically ordered core with uncompensated surface spins yielding μp and the surface spins order in a spin-glass-like state below TB, possibly due to interparticle interactions.

scholarly journals Consideration of Magnetic Measurements for Characterisation of Ferrite–Martensite Commercial Dual-Phase (DP) Steel and Basis for Optimisation of the Operating Magnetic Field for Open Loop Deployable Sensors

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 490
Author(s):  
Mohsen Aghadavoudi Jolfaei ◽  
Lei Zhou ◽  
Claire Davis
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Magnetic Measurements ◽  
Initial Permeability ◽  
Open Loop ◽  
Dual Phase ◽  
Dp Steel ◽  
Ferrite Fraction ◽  
Lift Off ◽  
Steel Properties

The magnetic properties of commercial dual-phase (DP) steels (DP600, DP800 and DP1000 grades) were evaluated using initial permeability, incremental permeability and coercivity and correlated with the key microstructural differences between the grades. The ferrite grain sizes and ferrite fractions have been compared with the magnetic parameters obtained from minor and major magnetisation loops within each DP grade. It has been revealed that the incremental permeability increases with the applied magnetic field amplitude to reach a peak and then drops at a higher magnetic field, with the values being different for the three DP grades at a lower field and converging to a similar permeability value at the high field. The effects of ferrite grain size and phase fraction on the incremental permeability are considered, and it has been shown that the influence of ferrite grain boundaries on magnetic permeability is more dominant than the effect of ferrite fraction in commercial DP steel samples. An analysis of the correlation between coercivity and initial permeability with tensile strength shows that the initial permeability provides a slightly better prediction of strength for the steels examined, which is believed to be due to the fact that a combination of reversible and irreversible domain components affect the coercivity value, while the initial permeability is predominantly affected by reversible domain movements. Based on the trend between incremental permeability and applied magnetic field and the commercial EM sensor (EMspec) operating parameters, the effect of lift-off and hence magnetic field strength on the sensitivity to DP steel properties can be assessed.

MAGNETIC HYSTERESIS OF HIGH-TEMPERATURE YBa2Cu3Ox-AgO SUPERCONDUCTORS: EXPLANATION OF MAGNETIC SUSPENSION

1988 ◽  
Vol 02 (07) ◽  
pp. 869-874 ◽  
Author(s):  
C.Y. HUANG ◽  
Y. SHAPIRA ◽  
E.J. MCNIFF ◽  
P.N. PETERS ◽  
B.B. SCHWARTZ ◽  
...  
Keyword(s):  
Magnetic Field ◽  
High Temperature ◽  
Simple Model ◽  
Hysteresis Loop ◽  
Applied Magnetic Field ◽  
Magnetic Hysteresis ◽  
Magnetic Suspension ◽  
Pinning Centers ◽  
Strong Pinning

We have measured the magnetization M of superconducting YBa 2 Cu 3 O x- AgO composites with T c approximately equal to 92K as a function of an applied magnetic field H at 77 and 87K. A very pronounced M-H hysteresis loop occurs even at 87K, indicating the presence of extremely strong pinning centers. The results of these measurements, together with a simple model, explain quantitatively why these superconductors could be suspended below a magnet.

3D Monte Carlo Simulations of Aggregate Structures in a Magnetic Colloidal Suspension Composed of Plate-Like Particles With Magnetic Moment Normal to the Particle Axis

2010 ◽  
Author(s):  
Yasuhiro Sakuda ◽  
Masayuki Aoshima ◽  
Akira Satoh
Keyword(s):  
Magnetic Field ◽  
Monte Carlo ◽  
Applied Magnetic Field ◽  
Magnetic Moment ◽  
Magnetic Particle ◽  
Colloidal Suspension ◽  
Magnetic Moments ◽  
Particle Interactions ◽  
Aggregate Structures ◽  
The Magnetic Field

We have investigated the internal aggregate structures of a colloidal suspension composed of magnetic plate-like particles with a magnetic moment normal to the particle axis by means of three-dimensional Monte Carlo simulations. In concrete, we have attempted to clarify the influences of the magnetic field strength, magnetic interactions between particles, and volumetric fraction of particles, on particle aggregation phenomena. In order to discuss quantitatively the aggregate structures of particles, we have focused on the radial distribution and orientational pair correlation function. For no applied magnetic field cases, long column-like clusters are formed as magnetic particle-particle interactions increase. Characteristics of these clusters are that particles incline in a certain direction with their magnetic moments alternating in direction between the neighboring particles. For applied magnetic field cases, the magnetic moments of the particles incline in the magnetic field direction, so that the columnar clusters are not formed. The brick wall-like aggregates are formed as the influences of the magnetic field and magnetic particle-particle interactions become significantly dominant.

Acoustic susceptibility of an insulating spin-glass in an applied magnetic field

1991 ◽  
Vol 1 (3) ◽  
pp. 415-440 ◽  
Author(s):  
P. Doussineau ◽  
A. Levelut ◽  
W. Schön
Keyword(s):  
Magnetic Field ◽  
Spin Glass ◽  
Applied Magnetic Field

MICROWAVE ABSORPTION STUDIES ON HIGH-Tc SUPERCONDUCTORS AND RELATED MATERIALS VIII — ESR OF DPPH COATED ON BiSrCaCuO FILMS FABRICATED ON MgO (100) SUBSTRATES

1992 ◽  
Vol 06 (14) ◽  
pp. 879-889
Author(s):  
K. SUGAWARA ◽  
S. TANAKA
Keyword(s):  
Magnetic Field ◽  
Film Thickness ◽  
Temperature Dependence ◽  
Applied Magnetic Field ◽  
Zero Field ◽  
Magnetic Field Effects ◽  
High Tc Superconductors ◽  
Thick Sample ◽  
High Tc ◽  
Absorption Studies

ESR of DPPH coated on Bi - Sr - Ca - Cu - O films fabricated on MgO (100) substrates by MOCVD have been studied for samples with different thicknesses, 1000 Å and 100 Å. Temperature dependence of the ESR peak-to-peak linewidth, ΔH pp , revealed that ΔH pp , increases with film thickness. The excess ESR linewidth, δ (ΔH pp ) was also analyzed in terms of (1-t)α, with t=T/T c , giving for example α=4±1 for the 1000 Å thick sample. The ESR lineshapes were distorted by rotating the samples in applied magnetic fields. Severe distortion was found for the 1000 Å sample below about 30 K, but the distortion almost disappears at temperatures above 30 K. The applied magnetic field effects were also examined in both field-cooled and zero-field-cooled cases.

HEAT CAPACITY OF YBa2Cu3O7−δ NEAR Tc

1989 ◽  
Vol 03 (02) ◽  
pp. 111-114 ◽  
Author(s):  
S.E. INDERHEES ◽  
M.B. SALAMON
Keyword(s):  
Magnetic Field ◽  
Heat Capacity ◽  
Applied Magnetic Field ◽  
Order Parameter ◽  
High Temperature Superconductor ◽  
Thermal Fluctuations ◽  
Zero Field ◽  
Ginzburg Landau ◽  
Fluctuation Effects ◽  
Heat Capacity Measurements

The exceptionally short Ginzburg-Landau coherence length of the high temperature superconductor YBa 2 Cu 3 O 7−δ makes possible the observation of fluctuation effects near the transition from the normal to the superconducting state. At the time of this writing, observations of fluctuation contributions to the electrical conductivity,1 magnetic susceptibility2 and thermopower3 have been reported. Excess contributions to the heat capacity (C fl ) due to thermal fluctuations, though far more difficult to observe, have been noted by several researchers.4 The heat capacity measurements are of particular interest, as a comparison of C fl above and below T c may elucidate the number of components of the Ginzburg-Landau (GL) order parameter and hence the nature of the pairing. The behavior of the heat capacity in an applied magnetic field is distinctly different from that of an ordinary superconductor.5 We summarize here our results on heat capacity measurements in zero field and in an applied magnetic field.

Magnetic Properties of the Gd1-xTbxNi3 Intermetallic Compounds

2011 ◽  
Vol 170 ◽  
pp. 109-113 ◽  
Author(s):  
Anna Bajorek ◽  
Grażyna Chełkowska ◽  
Artur Chrobak ◽  
Marzena Kwiecień-Grudziecka
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Curie Temperature ◽  
Saturation Magnetization ◽  
Intermetallic Compounds ◽  
Applied Magnetic Field ◽  
Magnetic Measurements ◽  
Zero Field ◽  
Zero Field Cooling ◽  
Field Cooling

The paper presents selected magnetic properties of the Gd1-xTbxNi3 intermetallic compounds. Based on the wide-ranging SQUID magnetometer (Quantum Design MPMS, temperature from 1.9K to 300K and magnetic field up to 7T) series of different magnetic measurements were carried out. In studied system the saturation magnetization and the Curie temperature strongly depends of Tb concentration. Moreover, the so-called field cooling - zero field cooling (FC-ZFC) curves reveal a dependence of M(T) on the applied magnetic field. The thermomagnetic curves indicate interesting behaviour which is typical for terbium compounds and can be ascribed to the interaction between different aligned magnetic subblattices.

IX.—The Control Field in Magnetic Hysteresis

1925 ◽  
Vol 44 ◽  
pp. 84-87
Author(s):  
Robert Cochran Gray
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Applied Magnetic Field ◽  
Magnetic Moment ◽  
Magnetic Hysteresis ◽  
Control Field ◽  
Magnetic Atom

Ewing's theory of the construction of a magnetic atom separates the atom into two portions: (a) the Weber element, possessing constant magnetic moment and capable of turning in response to an applied magnetic field; and (b) an outer (or inner) group of fixed “magnets” (i.e. electrons moving in orbits), which have like poles all directed towards the centre of the atom. Owing to the want of symmetry of the elements composing the group or shell, there are several magnetic fields, each of different direction, acting in the neighbourhood of the Weber element, and the direction of each of these represents a position of stability of the Weber element.

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