Magnetocaloric Effect in Nanosystems Based on Ferromagnets with Different Curie Temperatures

Abstract The magnetocaloric effect in nanosystems based on exchange-coupled ferromagnets with different Curie temperatures is calculated within the mean-field theory. Good agreement between the results of the mean-field theory and the Landau theory, valid near the critical phase transition temperature, is demonstrated for a flat-layered Fe/Gd/Fe structure. We show that a high magnetic cooling efficiency in this system is attainable in principle and prove the validity of the Maxwell relation, enabling an experimental verification of the predictions made. The theory developed for flat-layered structures is generalized to a granular medium.

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Modeling the Magnetocaloric Effect of La0.8MnO3 by the Mean-Field Theory

Journal of Superconductivity and Novel Magnetism ◽

10.1007/s10948-019-05316-0 ◽

2019 ◽

Vol 33 (4) ◽

pp. 1143-1149

Author(s):

C. Henchiri ◽

A. Benali ◽

T. Mnasri ◽

M. A. Valente ◽

E. Dhahri

Keyword(s):

Field Theory ◽

Magnetocaloric Effect ◽

Mean Field Theory ◽

Mean Field ◽

The Mean

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The nuclear relaxation rate for the itinerant-electron antiferromagnet

Canadian Journal of Physics ◽

10.1139/p82-089 ◽

1982 ◽

Vol 60 (5) ◽

pp. 649-653 ◽

Cited By ~ 1

Author(s):

M. Crişan ◽

Zs. Gulácsi

Keyword(s):

Field Theory ◽

Relaxation Rate ◽

Mean Field Theory ◽

Mean Field ◽

Band Model ◽

Itinerant Electron ◽

Nuclear Relaxation ◽

The Mean ◽

Two Band Model ◽

Good Agreement

The relaxation rate in the nuclear magnetic resonance of the itinerant-electron antiferromagnet was calculated as a function of temperature. A good agreement with the experimental results obtained on CrB2 has been observed. The two band model for the itinerant-electron antiferromagnet for T < TN (TN is the critical temperature) and the mean field theory for the critical region have been used to calculate [Formula: see text] as a function of temperature.

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The Mean-Field Theory for the Study of the Magnetocaloric Effect of Nd0.67Ba0.33Mn0.98Fe0.02O3 Manganite

Journal of Superconductivity and Novel Magnetism ◽

10.1007/s10948-017-4259-2 ◽

2017 ◽

Vol 31 (3) ◽

pp. 841-848 ◽

Cited By ~ 5

Author(s):

Mohamed Hsini ◽

Sobhi Hcini ◽

Michel Boudard ◽

Sadok Zemni

Keyword(s):

Field Theory ◽

Magnetocaloric Effect ◽

Mean Field Theory ◽

Mean Field ◽

The Mean

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Modeling the Magnetocaloric Effect of Nd0.67Ba0.33Mn0.98 Fe0.02O3 by the Mean Field Theory

Magnetometers - Fundamentals and Applications of Magnetism ◽

10.5772/intechopen.82559 ◽

2020 ◽

Author(s):

Mohamed Hsini ◽

Sadok Zemni

Keyword(s):

Field Theory ◽

Phase Transition ◽

Magnetic Properties ◽

Magnetic Fields ◽

Magnetocaloric Effect ◽

Mean Field Theory ◽

Mean Field ◽

Entropy Change ◽

Magnetization Curves ◽

The Mean

In this paper, we have exploited the mean field theory combined with the Bean-Rodbell model to justify the magnetocaloric effect (MCE) in Nd0.67Ba0.33Mn0.98Fe0.02O3 sample. The simulation of some magnetic properties has been investigated. Modeling magnetization curves have been successfully achieved using this model. The second-order ferromagnetic-paramagnetic (FM-PM) phase transition of our system has been verified through the value of the parameter which controls the transition nature in the Bean-Rodbell model. Theoretical and experimental expressions, which have rated the magnetic entropy change ( − ∆ S M ) under various magnetic fields, have been derived. Theoretical ( − ∆ S M ) curves have been compared to the experimental ones.

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