scholarly journals Магнитные свойства двухфазных магнитных боросиликатных стекол, содержащих наночастицы beta-Fe-=SUB=-2-=/SUB=-O-=SUB=-3-=/SUB=- и Fe-=SUB=-3-=/SUB=-O-=SUB=-4-=/SUB=-

2020 ◽  
Vol 46 (16) ◽  
pp. 28
Author(s):  
С.А. Борисов ◽  
А.А. Набережнов ◽  
B. Nacke ◽  
A. Nikanorov
Keyword(s):  
Magnetic Properties ◽  
Magnetic Fields ◽  
Fe3o4 Nanoparticles ◽  
Superparamagnetic Nanoparticles ◽  
Blocking Temperature ◽  
Neel Temperature ◽  
Specific Magnetization ◽  
Borosilicate Glasses ◽  
Néel Temperature ◽  
Two Phase

The magnetic properties of two-phase borosilicate glasses containing in the skeleton a mixture of β-Fe2O3 and Fe3O4 nanoparticles have been studied. The sizes of nanoparticles have been determined, the value of blocking temperature (TB ~ 330 K) for ensemble of superparamagnetic nanoparticles is obtained. It is shown that in the high applied magnetic fields the specific magnetization of these glasses increases sharply at approaching and below Neel temperature for the bulk β-Fe2O3.

Magnetic Properties of Two-Phase Borosilicate Glasses Containing β-Fe2O3 and Fe3O4 Nanoparticles

2020 ◽  
Vol 46 (8) ◽  
pp. 808-811
Author(s):  
S. A. Borisov ◽  
A. A. Naberezhnov ◽  
B. Nacke ◽  
A. Nikanorov
Keyword(s):  
Magnetic Properties ◽  
Fe3o4 Nanoparticles ◽  
Borosilicate Glasses ◽  
Two Phase

scholarly journals Morphology and Magnetic Properties of Ferriferous Two-Phase Sodium Borosilicate Glasses

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Alexander Naberezhnov ◽  
Nadezda Porechnaya ◽  
Viktor Nizhankovskii ◽  
Alexey Filimonov ◽  
Bernard Nacke
Keyword(s):  
Magnetic Properties ◽  
Iron Oxides ◽  
Channel Structure ◽  
Borosilicate Glasses ◽  
Melt Quenching ◽  
Two Phase ◽  
Furnace Charge ◽  
Self Assembling ◽  
Quenching Method ◽  
Drop Structure

This contribution is devoted to the study of morphology and magnetic properties of sodium borosilicate glasses with different concentrations (15, 20, and 25 wt.%) ofα-Fe2O3in an initial furnace charge. These glasses were prepared by a melt-quenching method. For all glasses a coexistence of drop-like and two-phase interpenetrative structures is observed. The most part of a drop structure is formed by self-assembling iron oxides particles. All types of glasses demonstrate the magnetic properties and can be used for preparation of porous magnetic matrices with nanometer through dendrite channel structure.

Magnetic properties improvement in Fe3O4 nanoparticles grown under magnetic fields

2004 ◽  
Vol 266 (4) ◽  
pp. 500-504 ◽  
Author(s):  
Jun Wang ◽  
Kai Zhang ◽  
Zhenmeng Peng ◽  
Qianwang Chen
Keyword(s):  
Magnetic Properties ◽  
Magnetic Fields ◽  
Fe3o4 Nanoparticles

THEORETICAL MODELS FOR MAGNETIC PROPERTIES OF IRON PNICTIDES

2013 ◽  
Vol 27 (16) ◽  
pp. 1350071 ◽  
Author(s):  
M. VUJINOVIĆ ◽  
M. PANTIĆ ◽  
D. KAPOR ◽  
P. MALI
Keyword(s):  
Magnetic Properties ◽  
Heisenberg Model ◽  
Degrees Of Freedom ◽  
Random Phase ◽  
Three Dimensional ◽  
Theoretical Models ◽  
Wave Dispersion ◽  
Model Parameters ◽  
Neel Temperature ◽  
Néel Temperature

We attempt to describe the magnetic properties of parent pnictide compounds by using both the J1–J2 Heisenberg model and its three-dimensional generalization, the J1–J2–Jc model. We also include spin anisotropy in the XY plane. In order to obtain the average magnetization and spin wave dispersion, we use the Green's functions method for spin operators in the random phase approximation. We obtain estimates for the model parameters by considering the low temperature experimental dispersion for the compounds CaFe 2 As 2 and BaFe 2 As 2 and conclude that theoretical dispersion can fit the experimental one if spatially anisotropic Hamiltonian is used. A good agreement between theory and experiment indicates that the Heisenberg model is applicable to parent pnictides at low temperatures. The applicability of the model for higher temperatures is checked by calculating the Néel temperature for both compounds. It turns out that the model overestimates the measured critical temperature. The Heisenberg model is not applicable to parent pnictides, for temperature comparable to Néel temperature. Our results thus confirm that all the magnetic properties of parent pnictides cannot be described with purely localized degrees of freedom, and that the itinerant magnetism should have an important role in these compounds. All results given in Sec. 3 are general and could be used in description of classes of compounds with spin stripe structure.

MAGNETIC PROPERTIES STUDY OF SOL–GEL SYNTHESIZED COBALT-DOPED ANATASE TiO2 NANOPOWDER

2011 ◽  
Vol 10 (04n05) ◽  
pp. 581-585
Author(s):  
BISWAJIT CHOUDHURY ◽  
AMARJYOTI CHOUDHURY ◽  
RAJENDRA K SINGH
Keyword(s):  
Magnetic Measurements ◽  
Anatase Phase ◽  
Sol Gel ◽  
Weak Ferromagnetism ◽  
Annealed Sample ◽  
Blocking Temperature ◽  
Neel Temperature ◽  
Néel Temperature ◽  
Tem Analysis ◽  
Key Factor

Co doped TiO2 nanopowder has been synthesized by a simple sol–gel route. XRD and TEM analysis confirms anatase phase of TiO2 with crystallite and particle sizes of 10 and 15 nm respectively. Presence of Co is confirmed by EDX. FTIR shows a slight shift in the Ti-O bonding vibration to lower frequency suggesting dopant incorporation on Ti site. For magnetic measurements the sample with dopant amount x = 0.075 is annealed both in vacuum and air. Weak ferromagnetism and a blocking temperature of 39 K is obtained for vacuum annealed sample while ferromagnetism is lost in the air annealed sample and shows only paramagnetic behavior. Temperature dependent magnetic measurements for air annealed sample shows antiferromagnetic behavior with a Neel temperature of 36.51 K. Here we report that oxygen vacancy and cobalt aggregates is a key factor for inducing ferromagnetism–superparamagnetism in vacuum annealed sample. Appearance of Neel temperature reveals the presence of antiferromagnetic Co3O4 which is the oxidation results of metallic Co or cobalt clusters present on host TiO2 surface.

The Néel temperature of TMMC in large magnetic fields

1977 ◽  
Vol 62 (6) ◽  
pp. 453-455 ◽  
Author(s):  
J.P. Groen ◽  
T.O. Klaassen ◽  
N.J. Poulis
Keyword(s):  
Magnetic Fields ◽  
Neel Temperature ◽  
Néel Temperature

Effect of thermal aging on the Néel temperature of a Fe–Cr–Ni–Mo alloy

2002 ◽  
Vol 17 (4) ◽  
pp. 879-883 ◽  
Author(s):  
C. H. Shek ◽  
M. W. Lai ◽  
J. K. L. Lai
Keyword(s):  
Magnetic Properties ◽  
Thermal Aging ◽  
Magnetic Transition ◽  
Neel Temperature ◽  
Néel Temperature ◽  
Detailed Mechanism

Numerous previous investigations on the magnetic properties of Fe–Cr–Ni or similar alloys show that the Néel temperature of this class of material is usually in the range 20–40 K and never exceeds 60 K. In this paper, we report on the discovery that the Ne’el temperature of a Fe–Cr–Ni–Mo alloy can be substantially increased to approximately 80–100 K by long-term thermal aging at 800 °C and above. This discovery has raised many questions on the detailed mechanism of magnetic transition on this class of material and is expected to open up a new line of investigation for researchers in this field.

Observation of transitions to spin‐slip structures and splitting of the Néel temperature of holmium in magnetic fields

1990 ◽  
Vol 67 (9) ◽  
pp. 5277-5279 ◽  
Author(s):  
Frank Willis ◽  
Naushad Ali ◽  
M. O. Steinitz ◽  
Mojtaba Kahrizi ◽  
D. A. Tindall
Keyword(s):  
Magnetic Fields ◽  
Neel Temperature ◽  
Néel Temperature

Peculiarities of Transport, Resonance and Optical Properties of the Anion-Substituted Manganese Chalcogenides

2015 ◽  
Vol 233-234 ◽  
pp. 447-450 ◽  
Author(s):  
O.B. Romanova ◽  
Sergei S. Aplesnin ◽  
A.M. Vorotynov ◽  
G.I. Makovetskii ◽  
O.F. Demidenko ◽  
...  
Keyword(s):  
Optical Properties ◽  
Magnetic Fields ◽  
Electron Structure ◽  
Optical Methods ◽  
Neel Temperature ◽  
Magnetoresistance Effect ◽  
Néel Temperature ◽  
Temperature Range ◽  
Maximum Value

The transport, resonance and optical properties of anion-substituted manganese chalcogenides MnSe1-xTex in the 77-300 K temperature range in magnetic fields up to 1T are studied. The magnetoresistance effect with the maximum value in the vicinity of the Neel temperature for the composition x = 0.1 is revealed. EPR data indirectly indicate the type of the current carriers – lattice polarons. The changes in electron structure occurring due to the anionic substitution are studied using the optical methods.

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