scholarly journals Magnetization and magnetic entropy change of a three-dimensional isotropic ferromagnet near the Curie temperature in the random phase approximation

2013 ◽  
Vol 416 ◽  
pp. 29-32 ◽  
Author(s):  
E.E. Kokorina ◽  
M.V. Medvedev
Keyword(s):  
Curie Temperature ◽  
Random Phase Approximation ◽  
Magnetic Entropy Change ◽  
Random Phase ◽  
Three Dimensional ◽  
Entropy Change ◽  
Phase Approximation ◽  
Magnetic Entropy

scholarly journals Magnetic properties of the non-stoichiometric TbCo2Nix alloys

2018 ◽  
Vol 185 ◽  
pp. 04021
Author(s):  
Alexander Inishev ◽  
Evgeny Gerasimov ◽  
Nikolay Mushnikov ◽  
Pavel Terentev ◽  
Vasily Gaviko
Keyword(s):  
Magnetic Properties ◽  
Curie Temperature ◽  
Concentration Dependence ◽  
Magnetic Moment ◽  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Magnetic Entropy ◽  
Thermodynamic Relation ◽  
Temperature Dependences

The magnetic and magnetothermal properties of the non-stoichiometric TbCo2Nix (0 ≤ x ≤ 0.2) alloys were studied. It was found that the concentration dependence of the Curie temperature and magnetic moment of the 3d-sublattice have a maximum at x = 0.025. The obtained experimental magnetic properties of the TbCo2Nix alloys were discussed under assumption that the Co magnetic moment in the compounds changes with increasing x. The magnetic entropy change was determined using the temperature dependences of the magnetization and Maxwell’s thermodynamic relation. The obtained results for TbCo2Nix were compared with those for the ErCo2Mnx alloys.

Study of Magnetic Transition and Magnetocaloric Effect in La1-xSrxMnO3 (0.20≤ x ≤0.35) Compounds

2013 ◽  
Vol 378 ◽  
pp. 225-229 ◽  
Author(s):  
Yeong Seung Jeong ◽  
M.S. Anwar ◽  
Faheem Ahmed ◽  
Seung Rok Lee ◽  
Bon Heun Koo
Keyword(s):  
Curie Temperature ◽  
Magnetic Entropy Change ◽  
Perovskite Phase ◽  
Magnetic Transition ◽  
Entropy Change ◽  
Solid State Reaction Method ◽  
Magnetic Entropy ◽  
Conventional Solid State Reaction ◽  
Ionic Radii ◽  
The Difference

We report the magnetic transition and large magnetic entropy change in Sr doped lanthanum manganites. Polycrystalline La1-xSrxMnO3(0.20x0.35) samples were prepared using the conventional solid-state reaction method. The results of X-ray diffraction indicates perovskite phase without any impurity. The magnetic study has revealed that the Curie temperature is influenced by Sr-concentration. The doping of Sr at La site affects the Mn-O bond length and Mn-O-Mn bond angle due to the difference in their ionic radii, consequently, the Curie temperature changed. A large magnetic entropy change has been observed for La0.8Sr0.2MnO3sample, the value of the maximum entropy change (SMmax) increases from 1.42 to 2.74 J/kgK as magnetic field increases from 1 to 2.5 T. This investigation suggests that La1-xSrxMnO3can be used as a potential magnetic refrigeration material.

Study on Influence of Ca2+ Ions Doping at a Site on Magnetic Properties and Magnetocaloric Effect of Nominal Compositions La1.4Sr1.6-xCaxMn2O7

2015 ◽  
Vol 1120-1121 ◽  
pp. 406-413 ◽  
Author(s):  
Yun Zong ◽  
Di Kang
Keyword(s):  
Curie Temperature ◽  
Manganese Oxides ◽  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Xrd Analysis ◽  
Layered Perovskite ◽  
Magnetic Entropy ◽  
Doping Amount ◽  
Space Group ◽  
Room Temperature Magnetic Refrigeration

Polycrystalline layered perovskite manganese oxides La1.4Sr1.6-xCaxMn2O7 (x=0,0.2,0.4,0.8,1.0,1.4,1.6) samples is prepared using solid state reaction.The XRD analysis shows that La1.4Sr1.6-xCaxMn2O7 (0 ≤ x ≤ 0.8) samples are Sr3Ti2O7-type tetragonal structure with space group I4/mmm and forms a layered perovskite structure; for the 1.0≤ x ≤1.6 series of samples the main phase is ABO3 type orthorhombic structure with space group Pbnm.For small amount of Ca2+ ion-doped sample (x= 0.2,0.4), induce serious Jahn-Teller(J-T) distortion of MnO6 octahedral.For a large number of doping (1.0≤ x ≤1.6) samples, ferromagnetic - paramagnetic transition occurs near the Curie temperature (Tc) from low to high temperatures.With increasing doping amount, the magnetization reached maximum at x=1.4 samples.Maximum magnetic entropy change of the three samples(x=1.0,1.4,1.6) reaches 0.84, 1.20 and 2.28 J kg-1 K-1 at 320,268 and 215K near the Curie temperature, respectively. The large magnetic entropy change effect under low magnetic field of the sample makes it an optimal candidate of room temperature magnetic refrigeration materials.

Field Dependence of the Refrigerant Capacity for La0.6Ca0.4MnO3 Manganite

2009 ◽  
Vol 154 ◽  
pp. 163-168 ◽  
Author(s):  
R.A. Szymczak ◽  
Aleksandra Kolano-Burian ◽  
Roman Kolano ◽  
R. Puzniak ◽  
V.P. Dyakonov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Curie Temperature ◽  
Statistical Model ◽  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Relative Cooling Power ◽  
Cooling Power ◽  
Magnetic Entropy ◽  
Refrigerant Capacity ◽  
Jahn Teller

The magnetocaloric effect in La0.6Ca0.4MnO3 manganite has been investigated. The isothermal magnetization versus applied magnetic field at various temperatures in the vicinity of Curie temperature was measured, and the temperature dependence of magnetic entropy change was determined using Maxwell’s relation. This value is comparable to that in Gd. Nevertheless, the relative cooling power of La0.6Ca0.4MnO3 was shown to be considerably lower than that of Gd. The experimental results have been analyzed in frames of a phenomenological statistical model. This model considers explicitly Jahn-Teller interactions and allows prediction of the field dependences of the magnetic entropy change and the relative cooling power.

The Curie temperature of a Heisenberg-Ising ferromagnet with uniaxial anisotropy

1982 ◽  
Vol 60 (3) ◽  
pp. 273-278 ◽  
Author(s):  
M. Tiwari ◽  
R. N. Srivastava
Keyword(s):  
Green Function ◽  
Curie Temperature ◽  
Random Phase Approximation ◽  
Random Phase ◽  
Uniaxial Anisotropy ◽  
Function Technique ◽  
Phase Approximation ◽  
Ising Ferromagnet ◽  
The Green Function

Effects of Ising anisotropy on Curie temperature have been studied in the presence of single ion anisotropy for a spin S = 1 system. The Green function technique with random phase approximation has been used taking into account all possible intersite correlations.

scholarly journals On the broadening of the magnetic entropy change due to Curie temperature distribution

2014 ◽  
Vol 115 (17) ◽  
pp. 17A929 ◽  
Author(s):  
Pablo Alvarez-Alonso ◽  
José L. Sánchez Llamazares ◽  
César F. Sánchez-Valdés ◽  
Gabriel J. Cuello ◽  
Victorino Franco ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Curie Temperature ◽  
Magnetic Entropy Change ◽  
Entropy Change ◽  
Magnetic Entropy

scholarly journals Compositional Dependence of Curie Temperature and Magnetic Entropy Change in the Amorphous Tb–Co Ribbons

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1002
Author(s):  
Xin Wang ◽  
Ding Ding ◽  
Li Cui ◽  
Lei Xia
Keyword(s):  
Curie Temperature ◽  
Linear Relationship ◽  
Metallic Glasses ◽  
Amorphous Alloys ◽  
Magnetic Entropy Change ◽  
Alloy Composition ◽  
Entropy Change ◽  
Magnetic Entropy ◽  
Compositional Dependence ◽  
Curie Temperature Tc

The Curie temperature (Tc) and magnetic entropy change (−ΔSm), and their relationship to the alloy composition of Tb–Co metallic glasses, were studied systematically in this paper. It was found that, in contrast to the situation in amorphous Gd–Co ribbons, the dependence of Tc on Tb content and the maximum −ΔSm vs. Tc -2/3 plots in Tb–Co binary amorphous alloys do not follow a linear relationship, both of which are supposed to be closely related to the non-linear compositional dependence of Tb–Co interaction due to the existence of orbital momentum in Tb.

scholarly journals A new family of decanuclear Ln7Cr3 clusters exhibiting a magnetocaloric effect

RSC Advances ◽  
2021 ◽  
Vol 11 (28) ◽  
pp. 17346-17351
Author(s):  
Jia-Jia Yin ◽  
Tian-Qi Lu ◽  
Cheng Chen ◽  
Hai-Yan Shi ◽  
Gui-Lin Zhuang ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Magnetocaloric Effect ◽  
Magnetic Entropy Change ◽  
Three Dimensional ◽  
Entropy Change ◽  
Magnetic Entropy ◽  
One Dimensional ◽  
New Family

Two decanuclear Ln–Cr clusters Ln7Cr3 were obtained, which formed a three-dimensional framework with one-dimensional nanopore channel through hydrogen-bond and π-bond interactions. Gd7Cr3 had a magnetic entropy change of 21.1 J kg−1 K−1 at 5 K, 7 T.

Sign in / Sign up

Export Citation Format

Share Document