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.

Magnetic and magnetocaloric properties of Dy5Pd2: role of magnetic irreversibility

RSC Advances ◽  
2015 ◽  
Vol 5 (59) ◽  
pp. 47860-47865 ◽  
Author(s):  
Tapas Paramanik ◽  
Tapas Samanta ◽  
R. Ranganathan ◽  
I. Das
Keyword(s):  
Intermetallic Compound ◽  
Low Temperature ◽  
Magnetocaloric Effect ◽  
Temperature Region ◽  
Magnetocaloric Properties ◽  
Magnetic Irreversibility

In this report the origin of giant inverse magnetocaloric effect at low temperature region has been studied in cluster glass intermetallic compound Dy5Pd2. In this context the procedure to obtain reversible magnetocaloric effect using Maxwell’s relation has been described.

Octanuclear [NiII4LnIII4] complexes. Synthesis, crystal structures and magnetocaloric properties

2014 ◽  
Vol 43 (24) ◽  
pp. 9136-9142 ◽  
Author(s):  
Traian D. Pasatoiu ◽  
Alberto Ghirri ◽  
Augustin M. Madalan ◽  
Marco Affronte ◽  
Marius Andruh
Keyword(s):  
Magnetocaloric Effect ◽  
Crystal Structures ◽  
Temperature Range ◽  
Magnetocaloric Properties

Slow sorption of atmospheric CO2 yielded a [NiII4GdIII4] complex with a significant magnetocaloric effect in the 1–20 K temperature range.

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 Gaudefroyite: a mineral with excellent magnetocaloric effect suitable for liquefying hydrogen

2018 ◽  
Vol 6 (13) ◽  
pp. 5260-5264 ◽  
Author(s):  
Rukang Li ◽  
Guangjing Li ◽  
Colin Greaves
Keyword(s):  
Low Temperature ◽  
Magnetocaloric Effect ◽  
Natural Mineral ◽  
Magnetocaloric Properties

A natural mineral, gaudefroyite, displays excellent low temperature magnetocaloric properties that are suitable for liquefying hydrogen.

Giant low-field reversible magnetocaloric effect in HoCoGe compound

RSC Advances ◽  
2016 ◽  
Vol 6 (108) ◽  
pp. 106171-106176 ◽  
Author(s):  
Y. Zhang ◽  
Q. Y. Dong ◽  
L. C. Wang ◽  
M. Zhang ◽  
H. T. Yan ◽  
...  
Keyword(s):  
Low Temperature ◽  
Magnetocaloric Effect ◽  
Temperature Change ◽  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Magnetic Entropy ◽  
Temperature Range ◽  
Low Field ◽  
Adiabatic Temperature Change ◽  
Attractive Candidate

HoCoGe compound shows large magnetic entropy change and adiabatic temperature change, which makes it an attractive candidate for magnetic refrigeration in the low temperature range.

Multiple magnetic transitions and magnetocaloric effect in hydrothermally synthesized single crystalline La0.5Sr0.5MnO3nanowires

2012 ◽  
Vol 1454 ◽  
pp. 63-68 ◽  
Author(s):  
Sayan Chandra ◽  
Anis Biswas ◽  
Subarna Datta ◽  
Barnali Ghosh ◽  
A.K. Raychaudhuri ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
Low Temperature ◽  
Magnetocaloric Effect ◽  
Room Temperature ◽  
Magnetic State ◽  
Double Exchange ◽  
Synthesis Process ◽  
Theoretical Studies ◽  
Magnetic Transitions ◽  
Magnetocaloric Properties

ABSTRACTWe have successfully prepared La0.5Sr0.5MnO3nanowires using a novel hydrothermal synthesis process and studied their magnetic and magnetocaloric properties. The system exhibits an inverse magnetocaloric effect (IMCE) around 175 K indicating presence of significant AFM correlation. The MCE study reveals a clear paramagnetic (PM) to ferromagnetic (FM) transition near room temperature (T ~ 325K) which is followed by onset of AFM at lower temperatures. The development of the FM-like magnetic state at low temperature is attributed to the enhanced double exchange (DE) driven ferromagnetism in AFM state as predicted by recent theoretical studies.

scholarly journals Tuning the Magnetocaloric Properties of the La(Fe,Si)13 Compounds by Chemical Substitution and Light Element Insertion

2021 ◽  
Vol 7 (1) ◽  
pp. 13
Author(s):  
Valérie Paul-Boncour ◽  
Lotfi Bessais
Keyword(s):  
Curie Temperature ◽  
Room Temperature ◽  
Light Element ◽  
Magnetic Entropy ◽  
Element Insertion ◽  
Chemical Substitution ◽  
Magnetocaloric Properties ◽  
Methods Of Synthesis ◽  
Giant Magnetocaloric Effect ◽  
Curie Temperature Tc

LaFe13−xSix compounds exhibit a giant magnetocaloric effect and they are considered as a good magnetocaloric working substance for an environmentally friendly cooling technique. Nevertheless as the Curie temperature TC is around 200 K, it is necessary to tune TC near room temperature for magnetic refrigeration. In this work we present a review of the various methods of synthesis and shaping of the LaFe13−xSix type compounds as well as the influence of chemical substitution, light element insertion or combination of both on TC, magnetic entropy and adiabatic temperature variation (ΔSM and ΔTad), and stability upon cycling. The advantages and drawbacks of each method of preparation and type of element substitution/insertion are discussed. The implementation of these NaZn13 type materials in active magnetic refrigerator is presented and their performances are compared to that of Gd in prototypes.

scholarly journals Low-Temperature Magnetocaloric Properties of V12 Polyoxovanadate Molecular Magnet: A Theoretical Study

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4399 ◽  
Author(s):  
Karol Szałowski
Keyword(s):  
Low Temperature ◽  
Magnetocaloric Effect ◽  
Computational Study ◽  
Thermodynamic Description ◽  
Entropy Change ◽  
Molecular Magnet ◽  
Thermodynamic Quantities ◽  
Magnetocaloric Properties ◽  
Adiabatic Magnetization ◽  
Quantities Of Interest

The paper presents a computational study of the magnetocaloric properties of the V12 polyoxovanadate molecular magnet. The description is restricted to low-temperature range (below approximately 100 K), where the magnetic properties of the system in question can be sufficiently modelled by considering a tetramer that consists of four vanadium ions with spins S=1/2. The discussion is focused on the magnetocaloric effect in the cryogenic range. The exact and numerical diagonalization of the corresponding Hamiltonian is used in order to construct the thermodynamic description within a version of the canonical ensemble. The thermodynamic quantities of interest, such as magnetic entropy, specific heat, entropy change under isothermal magnetization/demagnetization, temperature change under adiabatic magnetization/demagnetization, refrigerant capacity, and magnetic Grüneisen ratio, are calculated and discussed extensively. The importance of two quantum level crossings for the described properties is emphasized. The significant ranges of direct and inverse magnetocaloric effect are predicted. In particular, the maximized inverse magnetocaloric response is found for cryogenic temperatures.

scholarly journals Magnetic and Magneto-Caloric Properties of the Amorphous Fe92−xZr8Bx Ribbons

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5334
Author(s):  
Xin Wang ◽  
Qiang Wang ◽  
Ben Zhen Tang ◽  
Ding Ding ◽  
Li Cui ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Curie Temperature ◽  
Saturation Magnetization ◽  
Maximum Entropy ◽  
Entropy Change ◽  
Boron Addition ◽  
Magnetocaloric Properties ◽  
Curie Temperature Tc

Magnetic and magnetocaloric properties of the amorphous Fe92−xZr8Bx ribbons were studied in this work. Fully amorphous Fe89Zr8B3, Fe88Zr8B4, and Fe87Zr8B5 ribbons were fabricated. The Curie temperature (Tc), saturation magnetization (Ms), and the maximum entropy change with the variation of a magnetic field (−ΔSmpeak) of the glassy ribbons were significantly improved by the boron addition. The mechanism for the enhanced Tc and −ΔSmpeak by boron addition was studied.

Magnetocaloric and Structural Studies of Substituted Tb0.2Dy0.8-xGdxCo0.9Al0.1 Laves Phases Alloys

2019 ◽  
Vol 806 ◽  
pp. 136-141 ◽  
Author(s):  
Galina Aleksandrovna Politova ◽  
Tatiana P. Kaminskaya ◽  
Aleksandra Mikhailova ◽  
Maksim Ganin ◽  
Olga Alekseeva ◽  
...  
Keyword(s):  
Rare Earth ◽  
Curie Temperature ◽  
Magnetocaloric Effect ◽  
Laves Phase ◽  
Surface Topology ◽  
Large Temperature ◽  
Structural Studies ◽  
Laves Phases ◽  
Al Substitution ◽  
Magnetocaloric Properties

The multicomponent Tb0.2Dy0.8-xGdxCo2 and Tb0.2Dy0.8-xGdxCo0.9Al0.1 alloys (x≤0.5) were studied in a large temperature range (80 – 350 K) and fields up to 1.8 T. Temperature dependencies of lattices parameters, surface topology features, Curie temperature and magnetocaloric effect near it, of these polycrystalline cubic Laves phase alloys have been obtained and analyzed. The effect of Gd and Al substitution within the rare earth and cobalt sublattices on the structural and magnetocaloric properties of Tb0.2Dy0.8Co2 has been discussed.

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