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

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.

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THEORETICAL MODELS FOR MAGNETIC PROPERTIES OF IRON PNICTIDES

International Journal of Modern Physics B ◽

10.1142/s0217979213500719 ◽

2013 ◽

Vol 27 (16) ◽

pp. 1350071 ◽

Cited By ~ 1

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.

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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=-

Письма в журнал технической физики ◽

10.21883/pjtf.2020.16.49850.18308 ◽

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.

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

Modern Physics Letters B ◽

10.1142/s0217984912500492 ◽

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.

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The synthesis and magnetic properties of BaFe2Se3 single crystals

RSC Advances ◽

10.1039/c7ra03031b ◽

2017 ◽

Vol 7 (48) ◽

pp. 30433-30438 ◽

Cited By ~ 5

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.

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Magnetic properties of NiO (nickel oxide) nanoparticles: Blocking temperature and Neel temperature

Journal of Alloys and Compounds ◽

10.1016/j.jallcom.2015.06.027 ◽

2015 ◽

Vol 647 ◽

pp. 1061-1068 ◽

Cited By ~ 70

Author(s):

Marin Tadic ◽

Dobrica Nikolic ◽

Matjaz Panjan ◽

Graeme R. Blake

Keyword(s):

Magnetic Properties ◽

Nickel Oxide ◽

Blocking Temperature ◽

Oxide Nanoparticles ◽

Neel Temperature ◽

Néel Temperature ◽

Nickel Oxide Nanoparticles

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An ab initio study of the magnetic properties of strontium hexaferrite

Scientific Reports ◽

10.1038/s41598-021-81028-7 ◽

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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