scholarly journals Magnetic Properties of Layered Heisenberg Ferromagnets

1993 ◽  
Vol 46 (4) ◽  
pp. 571 ◽  
Author(s):  
A Du ◽  
GZ Wei
Keyword(s):  
Magnetic Properties ◽  
Low Temperature ◽  
Curie Temperature ◽  
Temperature Region ◽  
Asymptotic Form ◽  
Interlayer Coupling ◽  
Arbitrary Spin ◽  
Spin Fluctuations ◽  
Asymptotic Expressions ◽  
Double Time

The double-time-temperature spin Green's function method is used to study the magnetic properties of layered ferromagnets with arbitrary spin S, within Tyablikov's decoupling approximation. According to the extent to which interlayer coupling suppresses twodimensional spin fluctuations, we divide the low-temperature region into two new ones, and give the asymptotic expressions for magnetisation and susceptibility over different temperature regions, including the low-temperature region, the vicinity of the Curie temperature and the high-temperature region. We also give the Curie temperature in an asymptotic form when inter layer coupling is weak.

scholarly journals Magnetic transformation in Ni-Mn-In Heusler alloy

Nukleonika ◽  
2015 ◽  
Vol 60 (3) ◽  
pp. 435-438
Author(s):  
Marian Kuzma ◽  
Wojciech Maziarz ◽  
Ireneusz Stefaniuk
Keyword(s):  
Magnetic Properties ◽  
Low Temperature ◽  
Ferromagnetic Resonance ◽  
Temperature Region ◽  
Heusler Alloy ◽  
Antiferromagnetic Interaction ◽  
Magnetic Transformation ◽  
Crystal Transformation ◽  
Crystal State ◽  
Martensitic State

Abstract Magnetic properties of a Ni50Mn35.5In14.5 Heusler ribbon were studied by ferromagnetic resonance (FMR) in the temperature range of 335–100 K. In the temperature region of 265–170 K, the FMR signal disappeared, in spite of the fact that this region comprised the main crystal transformation temperatures: Ms, Mf, As, Af. In the austenite crystal state, a weak antiferromagnetic interaction was observed, whereas ferromagnetism was detected in the low temperature martensitic state.

SPIN FLUCTUATIONS IN TCo2 STUDIED BY RESISTIVITY AND THERMOPOWER EXPERIMENTS (T = Y, Lu, Sc, Hf, Zr, Ce)

1993 ◽  
Vol 07 (01n03) ◽  
pp. 370-373 ◽  
Author(s):  
N. BARANOV ◽  
E. BAUER ◽  
E. GRATZ ◽  
R. HAUSER ◽  
A. MARKOSYAN ◽  
...  
Keyword(s):  
Low Temperature ◽  
Specific Heat ◽  
Temperature Dependence ◽  
Temperature Region ◽  
Low Temperatures ◽  
Spin Fluctuations ◽  
General Tendency ◽  
Electronic Specific Heat ◽  
Temperature Dependent

The temperature dependence of the resistivity and the thermopower in the region from 4.2K up to 1000K for the six isostructural paramagnetic compounds TCo 2 (T=Y, Lu, Sc, Hf, Zr, Ce) is studied. The resistivity ρ (T) follows a T 2 dependence at low temperatures in all these compounds. Plotting the A values into an A vs. γ2 diagram shows that YCo 2, LuCo 2, and ScCo 2 are spinfluctuation systems (A and γ denote the coefficients in ρ (T) = ρ0 + AT 2 and that of the electronic specific heat, respectively) HfCo 2 and ZrCo 2 do not fit into this general tendency in the ( A , γ2)-diagram. The temperature dependent thermopower S(T) in YCo 2, LuCo 2 and ScCo 2 exhibits a pronounced minimum in the low temperature region. These minima are obviously connected with the existence of spin fluctuations (paramagnon-drag). Spin fluctuations in HfCo 2 and ZrCo 2 are less important. This we conclude also from the ten times smaller A-values and the missing minimum in the thermopower at low temperatures.

scholarly journals Новые магнитные материалы на основе соединений RNi для криогенной техники

2020 ◽  
Vol 46 (6) ◽  
pp. 51
Author(s):  
В.Б. Чжан ◽  
И.С. Терёшина ◽  
А.А. Курганская ◽  
С.А. Лушников ◽  
В.Н. Вербецкий ◽  
...  
Keyword(s):  
Low Temperature ◽  
Curie Temperature ◽  
Magnetocaloric Effect ◽  
Temperature Region ◽  
Partial Substitution ◽  
Temperature Range ◽  
Magnetocaloric Properties ◽  
Cryogenic Engineering ◽  
Significant Change ◽  
Curie Temperature Tc

Magnetocaloric properties of compounds Gd(Ni0.98Si0.02), Dy(Ni0.95Si0.05) and their hydrides Gd(Ni0.98Si0.02)H3, Dy(Ni0.95Si0.05)H4 were investigated in the temperature range 2 – 100K. It was found that partial substitution of Ni atoms by Si atoms, as well as subsequent hydrogenation can lead to a significant change in the Curie temperature (TC), the magnetocaloric effect, and the temperature at which the maximum MCE (Tmax) is observed. It is shown that the TC and Tmax of the hydrides are shifted by several degrees to the low temperature region with increasing or maintaining the MCE, which can significantly expand the application of such materials in cryogenic engineering.

Depth trends in magnetic properties in an area of prolonged cold seawater drawdown in uppermost Troodos-type oceanic crust

1987 ◽  
Vol 24 (5) ◽  
pp. 941-952 ◽  
Author(s):  
James M. Hall ◽  
Charles Walls ◽  
Mark Williamson ◽  
Bing-Xi Wang
Keyword(s):  
Magnetic Properties ◽  
Low Temperature ◽  
Curie Temperature ◽  
Sedimentary Cover ◽  
Drill Core ◽  
Secondary Minerals ◽  
Troodos Ophiolite ◽  
Core Section ◽  
Discontinuous Nature ◽  
Magnetization Behaviour

Study of the oxide minerals and measurements of the magnetic properties of about 100 samples distributed over a 475 m continuous drill-core section from the uppermost part of an extrusive sequence of the Troodos, Cyprus, ophiolite close to 35°02′N, 33°11′E, in the vicinity of Malounda, yields the following principal results: (1) Low-temperature alteration is intense to a depth of 260 m, below which it is relatively much subdued. (2) Saturation magnetization, natural remanence intensity, and initial susceptibility all increase continuously with depth throughout the section. (3) Curie temperature decreases with depth to 260 m, below which a change in the style of the thermal decay of magnetization behaviour takes place. (4) Pillowed and massive flows differ in their magnetic properties.The results are consistent with the downwards decrease in low-temperature alteration also noted by K. Gillis from the distribution of secondary minerals. The downwards variations in magnetic properties closely follow in both sense and magnitude the trends observed in DSDP hole 417A, where marked downwards decrease in low-temperature alteration also occurs. This comparison and the discontinuous nature of the lower units of the Troodos sedimentary cover in the vicinity of hole CY-1 support the interpretation of the upper, reddened facies of the Troodos extrusive sequence as being due to prolonged drawdown of cold seawater and suggest that the magnetization of at least the upper part of the Troodos ophiolite is a reliable guide to ocean crust magnetization.

Magnetic Nanostructures Fabricated by Electrochemical Synthesis

2007 ◽  
Vol 121-123 ◽  
pp. 839-842 ◽  
Author(s):  
K. Keshoju ◽  
X. Gu ◽  
A.T. Kumar ◽  
L. Sun
Keyword(s):  
Thin Film ◽  
Magnetic Properties ◽  
Low Temperature ◽  
Curie Temperature ◽  
Magnetic Nanostructures ◽  
Cost Effective ◽  
Remnant Magnetization ◽  
Saturation Field ◽  
Alloy Electrodeposition ◽  
Nanoporous Structures

Electrochemical processing is a cost effective and low-temperature approach suitable for the fabrication of certain unique nanostructures that are difficult to obtain by other methods. Here we report on the synthesis of nanowires and nanoporous structures with the intention to control the magnetic properties of conventional materials. Nanowires with variable sizes (diameter 15 nm - microns, and length up to 100 microns) have been fabricated by template assisted electrodeposition. Utilizing a combined alloy electrodeposition and electrochemical dealloying approach, porous nanostructures with controlled pore size and porosity have also been synthesized. Magnetization, Curie temperature, coercivity, saturation field, and remnant magnetization of these magnetic nanostructures exhibit much wider tunibility compared to bulk and thin film samples.

scholarly journals Influence of non-magnetic Cu on enhancing the low temperature magnetic properties and Curie temperature of FeCoNiCrCu(x) high entropy alloys

2020 ◽  
Vol 182 ◽  
pp. 99-103 ◽  
Author(s):  
Varun Chaudhary ◽  
Vishal Soni ◽  
Bharat Gwalani ◽  
R.V. Ramanujan ◽  
Rajarshi Banerjee
Keyword(s):  
Magnetic Properties ◽  
Low Temperature ◽  
Curie Temperature ◽  
High Entropy Alloys ◽  
High Entropy

Structure, Magnetostriction and Magnetic Properties of the Mn100-xFex (x=50, 58) Alloys Prepared by SPS

2016 ◽  
Vol 848 ◽  
pp. 575-579
Author(s):  
Liang Zhou ◽  
Lei Ma ◽  
Shi Qian Zhao ◽  
Lin Yi Cheng ◽  
Yu Song Du
Keyword(s):  
Magnetic Properties ◽  
Low Temperature ◽  
Temperature Region ◽  
Strain Gauge ◽  
Magnetic Measurement ◽  
Ferromagnetic Phase ◽  
Gradual Transition ◽  
Plasma Sintering ◽  
Single Face ◽  
Spark Plasma

Mn100-xFex (x=50, 58) alloys were prepared by spark plasma sintering (SPS), and the structure, magnetostriction and magnetic properties of the polycrystalline Mn100-xFex alloys were investigated. The results of XRD and SEM showed that the as-cast and annealed samples presented a single face center cubic γ-phase, which is austenite structure. The magnetic measurement showed that Mn100-xFex (x=50, 58) alloys annealed at 700oC were a typical ferromagnet at low temperature and there was a gradual transition from the ferromagnetic phase to the paramagnetic phase in a wide temperature region (about 150-250K). The magnetostriction for the annealed samples, measured by strain-gauge bridge up to 3T, was ~100 ppm at 300K, but the results was chaotic. The results are not in agreement with the results reported. The further research on the mechanism of the magnetostriction is needed.

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