Compositional medium consisted of anisotropic ferrite particles inserted in nonmagnetic matrix

2008 ◽  
Author(s):  
V. I. Zubkov ◽  
V. I. Shcheglov
Keyword(s):  
Nonmagnetic Matrix

FMR line shift for γ-Fe2O3 magnetic nanoparticles embedded in a nonmagnetic matrix

2007 ◽  
Vol 244 (3) ◽  
pp. 859-865 ◽  
Author(s):  
N. Guskos ◽  
J. Typek ◽  
M. Maryniak
Keyword(s):  
Magnetic Nanoparticles ◽  
Line Shift ◽  
Nonmagnetic Matrix

Magnetic States of Nanoparticles with RKKY Interaction

2013 ◽  
Vol 774-776 ◽  
pp. 523-527 ◽  
Author(s):  
Valery I. Belokon ◽  
Konstantin V. Nefedev ◽  
Vitalii Y. Kapitan ◽  
Olga I. Dyachenko
Keyword(s):  
Spin Glass ◽  
Effective Magnetic Moment ◽  
Magnetic State ◽  
Field Method ◽  
Spherical Nanoparticles ◽  
Rkky Interaction ◽  
Interaction Field ◽  
Magnetic States ◽  
Antiferromagnetic Spin ◽  
Nonmagnetic Matrix

Conditions of phase transitions in systems of identical ferromagnetic spherical nanoparticles randomly distributed in metal nonmagnetic matrix and superlattices of small number of nanoparticles with the Ruderman-Kittel-Kasuya-Yosida interaction are researched. In the framework of the Ising model the behavior of superspins is well described with the random interaction field method. The alteration of the effective magnetic moment due to the change in volume affects the choice of the magnetic state of the system: ferromagnetic spin glass or antiferromagnetic spin glass. The ground state of superlattice depends on the distance between particles.

Microwave Properties of Sandwich Structure Based on Iron and Barium Nanoparticles

2009 ◽  
Vol 152-153 ◽  
pp. 337-340
Author(s):  
A.V. Babushkin
Keyword(s):  
High Frequency ◽  
Sandwich Structure ◽  
Effective Permeability ◽  
Skin Effect ◽  
Effective Medium Theory ◽  
Microwave Properties ◽  
Medium Theory ◽  
Magnetic Components ◽  
Damping Parameter ◽  
Nonmagnetic Matrix

The high frequency intrinsic and effective permeability was calculated for spherical iron and barium particles in a nonmagnetic matrix (epoxy resin) by using the combination of Landau-Lifshitz-Gilbert equation and extended Bruggeman’s effective medium theory with the consideration of the skin effect. It was found that the microwave properties of the composite were influenced by many parameters, such as damping parameter, volume fractions and size of magnetic components. The sandwich microwave absorber with reflection loss < −10 dB over the range of 6-22 GHz was achieved. The thickness of absorber is only 4.25 mm.

Evidence for Magnetic Polarons in Hole-Doped Cobalt Perovskites

2010 ◽  
Vol 1256 ◽  
Author(s):  
Andrey Podlesnyak ◽  
Albert Furrer ◽  
Thierry Straessle ◽  
Ekaterina Pomjakushina ◽  
Kazimierz Conder ◽  
...  
Keyword(s):  
Spin State ◽  
Ground State ◽  
Magnetic Impurities ◽  
Natural Analog ◽  
Magnetic Polarons ◽  
Intermediate Spin ◽  
Nonmagnetic Matrix ◽  
Very High ◽  
Ferromagnetic Particles ◽  
Spin Ground State

AbstractA substitution of La3+ by Sr2+ in LaCoO3 induces holes in the low-spin ground state of the Co ions, which behave like magnetic impurities with a very high spin value (13 μB per hole). In this work, using single-crystal neutron spectroscopy, we prove that the charges introduced by strontium doping do not remain localized at the cobalt sites. Instead, each hole not only creates Co4+ in low-spin state, but it also transforms the six nearest neighboring Co3+ ions to the intermediate-spin state thereby forming a magnetic seven-site (heptamer) polaron. Spin-state polarons behave like magnetic nanoparticles embedded in an insulating nonmagnetic matrix. Therefore, lightly doped La1-xSrxCoO3 is a natural analog to artificial structures composed of ferromagnetic particles in insulating matrices.

High frequency complex permeability of iron particles in a nonmagnetic matrix

2006 ◽  
Vol 99 (8) ◽  
pp. 083905 ◽  
Author(s):  
L. Z. Wu ◽  
J. Ding ◽  
H. B. Jiang ◽  
C. P. Neo ◽  
L. F. Chen ◽  
...  
Keyword(s):  
High Frequency ◽  
Complex Permeability ◽  
Iron Particles ◽  
Nonmagnetic Matrix

Lorentz microscopy of magnetic fine particles

1999 ◽  
Vol 5 (S2) ◽  
pp. 30-31
Author(s):  
T. Tanji ◽  
N. Aoyama ◽  
K. Yamamoto ◽  
T. Hirayama
Keyword(s):  
Fine Particles ◽  
Amorphous Film ◽  
Surface Topology ◽  
Magnetic Characteristics ◽  
Granular Film ◽  
Granular Films ◽  
Lorentz Microscopy ◽  
Fine Structures ◽  
The Relationship ◽  
Nonmagnetic Matrix

Magnetic granular films, which consist of magnetic fine particles of nanometer size and a nonmagnetic matrix, have been of great interest for new magnetic materials. Their magnetic characteristics strongly depend on the fine structures, besides the combination of magnetic and nonmagnetic constituents, especially their surface topology and the particles size. Although the relationship between these fine topological structures and the macro-magnetic characteristics has been investigated systematically by many researchers, there has remained a desire to observe magnetic microstructures directly. We succeeded in observing the magnetic structure of fine particles in granular films using Lorentz microscopy.Two kinds of specimens were observed. One was an Fe-Mo granular film. An amorphous film of Fe-Mo was prepared by dc magnetron sputtering on amorphous carbon thin films at a temperature below 180 K. The films were annealed at 770 K within an in-plane magnetic field. The other kind was an Fe-MgO granular film, where iron particles were embedded in a magnesium oxide single crystal.

Microstructural evolution and magnetic properties of size-controlled nanocrystalline Ni in Ni(OH)2–ZrO2 composite

2007 ◽  
Vol 22 (6) ◽  
pp. 1520-1526 ◽  
Author(s):  
Bibhuti B. Nayak ◽  
Satish Vitta ◽  
D. Bahadur
Keyword(s):  
Magnetic Properties ◽  
Reaction Time ◽  
Saturation Magnetization ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Reduction Reaction ◽  
Initial Reaction ◽  
X Ray ◽  
Size Controlled ◽  
Nonmagnetic Matrix

Size-controlled nanocrystallites of Ni varying in size from 2 to 26 nm distributed in a nonmagnetic matrix of Ni(OH)2–ZrO2have been prepared by changing the reduction reaction time and by adding different concentrations of ZrOCl2solution to the initial reaction mixture. X-ray photoelectron spectroscopy indicates the presence of B2O3, Ni(OH)2, and ZrO2with Ni nanocrystals in the as-prepared composites. The room-temperature saturation magnetization and coercivity of the composites increases from ∼1.5 to 10 emu g−1and 100 to 200 Oe, respectively, when the ZrOCl2concentration in the reaction mixture increases to 0.10 M. The nanocrystals prepared without the addition of ZrOCl2exhibit a typical ferromagnetic response at 300 K, while that prepared with the addition of 0.10 M ZrOCl2shows a ferromagnetic response up to 400 K with higher saturation magnetization and coercivity.

scholarly journals Effects of germanium on the electronic transport mechanism in Co20(Cu1-xGex)80 nanogranular ribbons

2002 ◽  
Vol 17 (12) ◽  
pp. 3050-3055
Author(s):  
J. He ◽  
Z. D. Zhang ◽  
J. P. Liu ◽  
D. J. Sellmyer
Keyword(s):  
Electronic Transport ◽  
Coulomb Blockade ◽  
Transport Mechanism ◽  
Giant Magnetoresistance ◽  
Transport Mechanisms ◽  
Electronic Spin ◽  
The Matrix ◽  
Spin Dependent Scattering ◽  
Electronic Tunneling ◽  
Nonmagnetic Matrix

The dependency of giant magnetoresistance (GMR) on the nonmagnetic matrix in nanogranular Co20(Cu1-xGex)80 ribbons was studied. When the matrix Cu is substituted with semiconductor Ge, the magnetoresistance transitioned from negative to positive at low temperatures. The positive GMR effect is closely related to the quantity of Co/Co3Ge2/Co junctionlike configurations. This result provides evidence for the competition between two types of electronic transport mechanisms in the magnetic granular ribbons: (i) electronic spin-dependent scattering, inducing a negative magnetoresistance and (ii) Coulomb blockade of the electronic tunneling, inducing a positive magnetoresistance.

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