scholarly journals Magnetic response of bovine spleen

2019 ◽  
Vol 18 (1) ◽  
pp. 52-58
Author(s):  
Ľubor Dlháň ◽  
Roman Krylov ◽  
Martin Kopáni ◽  
Roman Boča
Keyword(s):  
Magnetic Susceptibility ◽  
Field Dependence ◽  
Bifurcation Point ◽  
Magnetic Hysteresis ◽  
Blocking Temperature ◽  
Magnetic Response ◽  
Zero Field ◽  
Remnant Magnetization ◽  
Paramagnetic Behaviour ◽  
Organic Tissue

Abstract Bovine spleen has been used as a sample for deep magnetochemical investigation. Temperature dependence of the magnetic susceptibility and field dependence of the magnetization reveal a paramagnetic behaviour that violates the Curie law. The zero-field cooled magnetization and field cooled magnetization experiments show the bifurcation point at ca TC = 20 K and the blocking temperature TB = 10 K confirming a dominating portion of ferritin along with the organic tissue. There is a remnant magnetization at temperature below 20 K and the search for the magnetic hysteresis was positive.

scholarly journals Iron-Doped Lithium Tantalate Thin Films Deposited by Magnetron Sputtering: A Study of the Iron Role in the Structure and the Derived Magnetic Properties

Crystals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 50 ◽  
Author(s):  
Sergio David Villalobos Mendoza ◽  
José Trinidad Holguín Momaca ◽  
José Trinidad Elizalde Galindo ◽  
Diana María Carrillo Flores ◽  
Sion Federico Olive Méndez ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Blocking Temperature ◽  
Ferromagnetic Behavior ◽  
Zero Field ◽  
Cooling Curves ◽  
X Ray Diffraction ◽  
Field Cooling

Fe-doped LiTaO3 thin films with a low and high Fe concentration (labeled as LTO:Fe-LC and LTO:Fe-HC, respectively) were deposited by magnetron sputtering from two home-made targets. The dopant directly influenced the crystalline structure of the LiTaO3 thin films, causing the contraction of the unit cell, which was related to the incorporation of Fe3+ ions into the LiTaO3 structure, which occupied Li positions. This substitution was corroborated by Raman spectroscopy, where the bands associated with Li-O bonds broadened in the spectra of the samples. Magnetic hysteresis loops, zero-field cooling curves, and field cooling curves were obtained in a vibrating sample magnetometer. The LTO:Fe-HC sample demonstrates superparamagnetic behavior with a blocking temperature of 100 K, mainly associated with the appearance of Fe clusters in the thin film. On the other hand, a room temperature ferromagnetic behavior was found in the LTO:Fe-LC layer where saturation magnetization (3.80 kAm−1) and magnetic coercivities were not temperature-dependent. Moreover, the crystallinity and morphology of the samples were evaluated by X-ray diffraction and scanning electron microscopy, respectively.

scholarly journals Magnetic Cobalt and Cobalt Oxide Nanoparticles in Hyperbranched Polyester Polyol Matrix

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
O. I. Medvedeva ◽  
S. S. Kambulova ◽  
O. V. Bondar ◽  
A. R. Gataulina ◽  
N. A. Ulakhovich ◽  
...  
Keyword(s):  
Magnetic Hysteresis ◽  
Average Diameter ◽  
Physicochemical Characteristics ◽  
Blocking Temperature ◽  
Zero Field ◽  
Hyperbranched Polyester ◽  
Polyester Polyol ◽  
Cobalt Oxide Nanoparticles ◽  
Ft Ir ◽  
Co Nanoparticles

A series of cobalt (Co) and its oxides based nanoparticles were synthesized by using hyperbranched polyester polyol Boltorn H20 as a platform and sodium borohydride as a reducing agent. UV, FT-IR, XRD, NTA, and TEM methods were employed to obtain physicochemical characteristics of the products. The average diameter of Co nanoparticles was approximately 8.2±3.4 nm. Their magnetic properties, including hysteresis loop, field-cooled, and zero field-cooled curves were investigated. The nanoparticles exhibit superparamagnetism at room temperature, accompanied by magnetic hysteresis below the blocking temperature.

Superparamagnetic Behavior of Granular Co-C Films Consisting of Nanocrystalline Cobalt Encapsulated in Carbon

2000 ◽  
Vol 614 ◽  
Author(s):  
Hao Wang ◽  
S.P. Wong ◽  
W.Y. Cheung ◽  
N. Ke ◽  
M.F. Chiah ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Rutherford Backscattering Spectrometry ◽  
Magnetic Measurements ◽  
Magnetic Hysteresis ◽  
Blocking Temperature ◽  
Vacuum Arc ◽  
Zero Field ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy

ABSTRACTNanocomposite Co-C thin films of about 15 nm thick were prepared by pulsed filtered vacuum arc deposition. The films were characterized by x-ray photoelectron spectroscopy, non-Rutherford backscattering spectrometry, x-ray diffraction, magnetic force microscopy and magnetic measurements. The as-deposited films were amorphous. After annealing at 350°C for one hour in vacuum (< 10−3 Pa), the films were found to consist of nanocrystalline Co grains encapsulated in carbon. The superparamagnetism of the annealed Co36C64 film was demonstrated by the measurement of DC susceptibility and magnetic hysteresis using a SQUID magnetometer. The superparamagnetic relaxation blocking temperature was marked to be about 12K by the peak of the zero-field-cooled magnetization under a field of 100 Oe. The magnetic properties of these annealed granular Co-C films transform from superparamagnetism to ferromagnetism when the Co concentration increases.

scholarly journals Magnetic properties of iron oxide nanoparticles with a DMSA-modified surface

2021 ◽  
Vol 242 (1) ◽  
Author(s):  
K. Winiarczyk ◽  
W. Gac ◽  
M. Góral-Kowalczyk ◽  
Z. Surowiec
Keyword(s):  
Magnetic Properties ◽  
Magnetite Nanoparticles ◽  
Magnetic Hysteresis ◽  
Blocking Temperature ◽  
Synthesis Process ◽  
Physical Parameters ◽  
Zero Field ◽  
Powder Samples ◽  
Surface Modified ◽  
Field Cooling

AbstractThe magnetic properties of magnetite nanoparticles (Fe3O4 NPs) strongly depend on their chemical and physical parameters, which can be regulated by a controlled synthesis process. To improve the quality of the obtained nanoparticles, their surface is often modified with organic compounds (from the group of surfactants, sugars, proteins, or organic acid). In this study, we synthesized magnetite nanoparticles with a surface modified with the organic compound DMSA. Then, the nanocrystallites were characterized in terms of structure and morphology. To investigate the role of DMSA and to understand the adsorption mechanism, FTIR measurements were carried out. Using Mössbauer spectroscopy, we investigated temperature-induced changes in the magnetic properties of prepared samples. The spectra were recorded in a wide temperature range (from 4 K to 390 K) for two types of samples: powders and ferrofluids with various concentrations. In the case of powder samples, the superparamagnetic doublet appeared at room temperature. For magnetic suspensions, the spectra were more complicated. They consisted of superposition of asymmetrically broadened sextets and doublets, which was caused by the occurrence of long-range dipole-dipole interactions. These interactions affected the magnetic properties of the material and increased the blocking temperature. Additionally, the magnetic hysteresis and zero field cooling-field cooling (ZFC/FC) curves were measured with the use of a vibrating sample magnetometer.

scholarly journals Microstructure and Superparamagnetic Properties of Mg-Ni-Cd Ferrites Nanoparticles

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
M. M. Eltabey ◽  
A. M. Massoud ◽  
Cosmin Radu
Keyword(s):  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Anisotropy Constant ◽  
Blocking Temperature ◽  
Zero Field ◽  
Effective Anisotropy Constant ◽  
Crystallite Sizes ◽  
Coprecipitation Route ◽  
Average Size ◽  
Field Cooling

Magnesium substituted nickel cadmium ferrite nanoparticles MgxNi0.6−xCd0.4Fe2O4(fromx= 0 to 0.6 with step 0.1) have been synthesized by the chemical coprecipitation route. X-ray diffraction (XRD) and infrared spectroscopy (FTIR) revealed that the obtained powders have a single phase of cubic spinel structure. The crystallite sizes calculated from XRD data have been confirmed using transmission electron microscopy (TEM) showing that the powders are consisting of nanosized grains with an average size range 5–1.5 nm. Magnetic hysteresis loops were traced at 6.5 K as well as at room temperature using VSM. It was found that, due to the Mg2+-ions substitution, the values of saturation magnetizationMsfor the investigated samples were decreased, whereas the coercive fieldHcincreased. Both zero field cooling (ZFC) and field cooling (FC) curves are measured in the temperature range (6.5–350 K) and the values of blocking temperatureTBwere determined. No considerable variation in the values ofTBwas observed with increasing Mg-content, whereas the values of the effective anisotropy constantKeffwere increased.

Synthesis of Superparamagnetic Magnesium Ferrite Nanoparticles by Microwave-Hydrothermal Method

2004 ◽  
Vol 818 ◽  
Author(s):  
Seema Verma ◽  
Hari S. Potdar ◽  
Sadgopal K. Date ◽  
Pattayil A. Joy
Keyword(s):  
Size Distribution ◽  
Magnetic Hysteresis ◽  
Ferrite Nanoparticles ◽  
Blocking Temperature ◽  
High Coercivity ◽  
Average Particle ◽  
Zero Field ◽  
Magnesium Ferrite ◽  
Hysteresis Behavior ◽  
Microwave Hydrothermal

AbstractSuperparamagnetic magnesium ferrite, MgFe2O4, nanoparticles were synthesized under mild microwave hydrothermal (MH) conditions. Transmission electron microscopic studies showed that the average particle size of the ferrite obtained is ∼3 nm, with a narrow size distribution. Temperature dependent AC magnetic susceptibility measurements at 2 Oe showed characteristic feature of superparamagnetism with blocking temperature, TB, at 47 K. TB decreases with increasing DC magnetic field as evidenced by zero-field-cooled susceptibility studies at 50 and 500 Oe (TB = 38 and 27 K respectively). As a typical superparamagnetic behavior, the zero-field- cooled and the field-cooled magnetizations diverge below TB. Magnetic hysteresis behavior is observed below TB, with a high coercivity of 185 Oe at 12 K, and magnetic hysteresis behavior disappears when measured above TB. The results indicate that MH method is highly suitable for the synthesis of superparamagnetic ferrite nanoparticles of uniform size distribution.

scholarly journals The Molecular Zeeman Effect of Imines. I. Methanimine, its Molecular g-Tensor, its Magnetic Susceptibility Anisotropies, its Molecular Electric Quadrupole Moment, its Electric Field Gradient at the Nitrogen Nucleus, and its Nitrogen Spin-Rotation Coupling

1989 ◽  
Vol 44 (11) ◽  
pp. 1063-1078 ◽  
Author(s):  
H. Krause ◽  
D. H. Sutter
Keyword(s):  
Magnetic Susceptibility ◽  
Zeeman Effect ◽  
Electric Quadrupole ◽  
Spin Rotation ◽  
Coupling Constants ◽  
Zero Field ◽  
Quadrupole Moments ◽  
Magnetic Susceptibility Tensor ◽  
State Expectation ◽  
The Individual

Abstract The rotational Zeeman effect has been observed in methanimine which was produced from ethylenediamine by flash pyrolysis. The observed vibronic ground state expectation values of the molecular g-values, the magnetic susceptibility anisotropies and the molecular electric quadrupole moments are: gaa = -1.27099(22), gbb= -0.18975(7), gcc= -0.03440(8), 2ξaa-ξbb-ξcc = 12.49(19) · 10-6 ergG-2mol-1, 2ξbb-ξcc-ξaa = 5.22(11) · 10-6 ergG-2 mol-1 Qaa = 0.43(17) · 10-26esu cm2, Qbb= 1.08(10) · 10-26 esu cm2, and Qcc= -1.51 (26) . 10-26 esu cm2. With the TZVP ab initio value for the out-off plane electronic second moment as additional input, reliable values can be given also for the individual components of the magnetic susceptibility tensor and for the bulk susceptibility:ξ = (ξaa + ξbb + ξcc)/3=-13.13(88) · 10-6 erg G -2 mol-1. From low-J a-and b-type zero field transitions the spin-rotation coupling constants and the 14N nuclear quadrupole coupling constants could be redetermined with improved accuracy. These data are compared with our new theoretical results.

FORC analysis of magnetically soft microparticles embedded in a polymeric elastic environment

2022 ◽  
Author(s):  
Dmitry Yu Borin ◽  
Mikhail V Vaganov
Keyword(s):  
Particle Concentration ◽  
Magnetic Hysteresis ◽  
Magnetic Response ◽  
Soft Matrix ◽  
First Order ◽  
Matrix Elasticity ◽  
Intrinsic Coercivity ◽  
The Matrix ◽  
Soft Particles ◽  
Elastomer Composites

Abstract First-order reversal curve (FORC) analysis allows one to investigate composite magnetic materials by decomposing the magnetic response of a whole sample into individual responses of the elementary objects comprising the sample. In this work, we apply this technique to analysing silicone elastomer composites reinforced with ferromagnetic microparticles possessing low intrinsic coercivity. Even though the material of such particles does not demonstrate significant magnetic hysteresis, the soft matrix of the elastomers allows for the translational mobility of the particles and enables their magnetomechanical hysteresis which renders into a wasp-waisted major magnetization loop of the whole sample. It is demonstrated that the FORC diagrams of the composites contain characteristic wing features arising from the collective hysteretic magnetization of the magnetically soft particles. The influence of the matrix elasticity and particle concentration on the shape of the wing feature is investigated, and an approach to interpreting experimental FORC diagrams of the magnetically soft magnetoactive elastomers is proposed. The experimental data are in qualitative agreement with the results of the simulation of the particle magnetization process obtained using a model comprised of two magnetically soft particles embedded in an elastic environment.

scholarly journals Slow magnetisation relaxation in tetraoxolene-bridged rare earth complexes

2017 ◽  
Vol 46 (40) ◽  
pp. 13756-13767 ◽  
Author(s):  
Maja A. Dunstan ◽  
Elodie Rousset ◽  
Marie-Emmanuelle Boulon ◽  
Robert W. Gable ◽  
Lorenzo Sorace ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Rare Earth ◽  
Slow Relaxation ◽  
Rare Earth Complexes ◽  
Zero Field ◽  
Ac Magnetic Susceptibility ◽  
Quantum Tunnelling ◽  
Dc Magnetic Field

Two tetraoxolene-bridged dinuclear Dy(iii) complexes exhibit slow relaxation in ac magnetic susceptibility studies with zero-field quantum tunnelling of the magnetisation that is suppressed by the application of a dc magnetic field.

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