scholarly journals The synthesis and magnetic properties of BaFe2Se3 single crystals

RSC Advances ◽  
2017 ◽  
Vol 7 (48) ◽  
pp. 30433-30438 ◽  
Author(s):  
Juanjuan Gao ◽  
Yifei Teng ◽  
Wei Liu ◽  
Shufan Chen ◽  
Wenming Tong ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Single Crystals ◽  
Neel Temperature ◽  
Néel Temperature ◽  
Average Spin

BaFe2Se3 synthesised is antiferromagnetic with a lower Neel temperature than before, mainly because the average spin of iron sites has fluctuated.

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.

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.

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.

Phase Transition in Ultrathin Films

2014 ◽  
Vol 215 ◽  
pp. 227-232 ◽  
Author(s):  
Leonid L. Afremov ◽  
Aleksandr A. Petrov
Keyword(s):  
Phase Transition ◽  
Percolation Threshold ◽  
Ultrathin Films ◽  
Critical Concentration ◽  
Crystalline Lattice ◽  
Neel Temperature ◽  
Néel Temperature ◽  
Average Spin ◽  
Experimental Values

Within the frame of average spin the dependence of Neel temperature of ultrathin antiferromagnetic film for FCC crystalline lattice on its thickness and the concentration of magnetic atoms has been defined. The λ values calculated by us are close to experimental values obtained for the films СoO/SiO2. The increasing of thickness leads to decreasing of the critical concentration down to the value equal to percolation threshold.

STUDY OF NÉEL TEMPERATURE AND MULTIPLE PHASE COEXISTENCE IN Bi0.5Ca0.5-xBaxMnO3 (x = 0–0.10)

2012 ◽  
Vol 26 (08) ◽  
pp. 1250049
Author(s):  
RENWEN LI ◽  
LI PI ◽  
WEI TONG ◽  
LEI ZHANG ◽  
LANGSHENG LING ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Charge Ordering ◽  
Magnetic Data ◽  
Perovskite Manganites ◽  
Neel Temperature ◽  
Néel Temperature ◽  
Multiple Phase ◽  
Magnetic Analysis ◽  
Structural And Magnetic Properties ◽  
Lower Temperature

Structural and magnetic properties of Bi0.5 Ca0.5-xBaxMnO3 (x = 0, 0.03, 0.05, 0.07 and 0.10) samples with charge ordering (CO) state and C-type antiferromagnetic (AFM) magnetic structure have been studied systematically. With increasing Ba-doping level, both CO and AFM are weakened. From the micro-magnetic analysis, we clarify the ambiguity about the Néel temperature TN in bismuth-based perovskite manganites. We find that the paramagnetic (PM)-CO/AFM transition temperature TCO at high temperature is the onset temperature of the PM–AFM transition, while customarily so-called TN at low temperature indicates the finish of the PM–AFM transition. Both the macro- and micro-magnetic data show that, in all the samples, only AFM state coexists with PM matrix below CO transition and above TN, while AFM state coexists with ferromagnetic (FM) state and PM state at lower temperature below TN.

On the Neel temperature and magnetic domain wall movements of Ga2−xFexO3 single crystals grown by floating-zone technique

2014 ◽  
Vol 590 ◽  
pp. 459-464 ◽  
Author(s):  
B. Srimathy ◽  
Indranil Bhaumik ◽  
S. Ganesamoorthy ◽  
R. Bhatt ◽  
A.K. Karnal ◽  
...  
Keyword(s):  
Domain Wall ◽  
Single Crystals ◽  
Magnetic Domain ◽  
Neel Temperature ◽  
Floating Zone ◽  
Magnetic Domain Wall ◽  
Néel Temperature

Magnetic and Dielectric Properties of PbFeBO4 and PbMnBO4 Single Crystals

2014 ◽  
Vol 215 ◽  
pp. 372-377 ◽  
Author(s):  
A.I. Pankrats ◽  
K.A. Sablina ◽  
D.A. Velikanov ◽  
O.A. Bayukov ◽  
A.M. Vorotynov ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Curie Temperature ◽  
Single Crystal ◽  
Single Crystals ◽  
Neel Temperature ◽  
Strong Anisotropy ◽  
Néel Temperature ◽  
X Ray ◽  
Magnetic And Dielectric Properties ◽  
Magnetic Dielectric

PbFeBO4 and PbMnBO4 single crystals were synthesized. The X-ray, magnetic, dielectric, Mössbauer, and resonance investigations of the crystals were fulfilled. It is established that single-crystal PbFeBO4 is an antiferromagnet with a Néel temperature TN =114 K, while PbMnBO4 is a ferromagnet with a Curie temperature TC = 31 K. Both single-crystal compounds have a strong anisotropy of the magnetic and dielectric properties.

scholarly journals An ab initio study of the magnetic properties of strontium hexaferrite

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
C. Tejera-Centeno ◽  
S. Gallego ◽  
J. I. Cerdá
Keyword(s):  
Magnetic Properties ◽  
Ab Initio ◽  
Density Functional ◽  
Strontium Hexaferrite ◽  
Multiscale Approach ◽  
Neel Temperature ◽  
Néel Temperature ◽  
Hubbard U ◽  
Exchange Constants ◽  
O 19

AbstractThe magnetic properties of $${\text{SrFe}}_{12}{\text{O}}_{19}$$ SrFe 12 O 19 , a paradigmatic hexaferrite for permanent magnet applications, have been addressed in detail combining density functional theory including spin–orbit coupling and a Hubbard U term with Monte Carlo simulations. This multiscale approach allows to estimate the Néel temperature of the material from ab initio exchange constants, and to determine the influence of different computational conditions on the magnetic properties by direct comparison versus available experimental data. It is found that the dominant influence arises from the choice of the Hubbard U term, with a value in the 2–3 eV range as the most adequate to quantitatively reproduce the two most relevant magnetic properties of this material, namely: its large perpendicular magnetocrystalline anisotropy and its elevated Néel temperature.

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