Magnetocaloric Effect and Frustrations in One-Dimensional Magnets

Zarubin, A. V.; Kassan‐Ogly, F. A.; Medvedev, M. V.; Proshkin, A. I.

doi:10.4028/www.scientific.net/ssp.233-234.212

Cited by 5 publications

(6 citation statements)

References 12 publications

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“…We have also estimated the relative cooling power (RCP) given by: RCP = −∆S max × δT FWHM (14) where δT FWHM is the full-width at half maximum of ∆S max versus temperature, to evaluate the magnetic cooling efficiency. The RCP values correspond to the amount of heat transferred between the cold and hot sides in an ideal refrigeration cycle.…”

Section: Resultsmentioning

confidence: 99%

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Investigation of magnetocaloric effect: Stoner approximation vs DMFT

Igoshev

Некрасов

Павлов

et al. 2019

J. Phys.: Conf. Ser.

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A comparative study of the magnetocaloric effect (MCE) in metals within the single-band Hubbard model on the face-centered cubic (fcc) lattice using both mean-field (Stoner) approximation (MFA) and dynamical mean-field theory (DMFT) is done. The MCE is investigated in the case of second order magnetic phase transition from ferromagnet to paramagnet. To ensure presence of itinerant ferromagnetism in the Hubbard model the special case of spectrum parameters generating giant van Hove singularity at the bottom of the band is considered, while the Fermi level E f is in the vinicity of the band bottom. To compare MCE within MFA and DMFT temperature dependence of magnetization, total energy and finally entropy for a set of Coulomb interactions U at zero and finite values of magnetic field h for both methods were performed. Also one of the MCE potentials, isothermal entropy change, as a function of temperature ∆S (T ) for both MFA and DMFT is calculated. In the MFA, the expected maximum value of ∆S (T ) at the Curie temperature T C (∆S max ) quite significantly decreases while U grows. Similar but much weaker decreasing of ∆S max is found for DMFT results. The account of local quantum fluctuations results in larger values of ∆S max within DMFT than within MFA. A peak width of ∆S (T ) at half height is approximately the same for both methods. Another effect of DMFT local quantum fluctuations is the destruction of anomalous Curie temperature T C dependence on U present in MFA, which is invoked by an effect of giant van Hove singularity. However the relative cooling power (RCP) is very close in DMFT and MFA for the same model parameters and goes down

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Section: Resultsmentioning

confidence: 99%

“…MCE in presence of different types of anisotropy for antiferromagnets [9,10] and paramagnets with non-Kramers ions [11] and Van Vleck paramagnet [12] and Ising ferromagnet [13] was investigated. Also MCE for some exotic systems was studied [14].…”

Section: Introductionmentioning

confidence: 99%

Investigation of magnetocaloric effect: Stoner approximation vs DMFT

Igoshev

Некрасов

Павлов

et al. 2019

J. Phys.: Conf. Ser.

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“…In this regard, theoretical predictions and descriptions of materials showing an enhanced MCE create real opportunities for the effective selection of the construction for working magnetic-refrigeration devices. Of particular interest is the investigation of the MCE in various one-dimensional (1D) quantum spin models [4][5][6][7][8][9][10][11][12][13][14][15][16][17] and several coupled spinelectron systems [18][19][20][21]. The reason lies in a possibility of obtaining exact analytical or numerical results as well as in a potential use of these models for the explanation of MCE data measured for real magnetic compounds.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, coexistence of the above phenomena is also possible. Both conventional and inverse MCE can be found in magnetic systems with rich structure of the ground-state phase diagram, in particular, in various 1D models [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21], some multilayers [29] or even some finite structures [30][31][32].…”

Section: Introductionmentioning

confidence: 99%

Ground-state and magnetocaloric properties of a coupled spin–electron double-tetrahedral chain (exact study at the half filling)

Gálisová

Jakubczyk

2017

Physica A: Statistical Mechanics and its Applications

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Ground-state and magnetocaloric properties of a double-tetrahedral chain, in which nodal lattice sites occupied by the localized Ising spins regularly alternate with triangular clusters half filled with mobile electrons, are exactly investigated by using the transfer-matrix method in combination with the construction of the Nth tensor power of the discrete Fourier transformation. It is shown that the ground state of the model is formed by two non-chiral phases with the zero residual entropy and two chiral phases with the finite residual entropy S = Nk B ln 2. Depending on the character of the exchange interaction between the localized Ising spins and mobile electrons, one or three magnetization plateaus can be observed in the magnetization process. Their heights basically depend on the values of Landé g-factors of the Ising spins and mobile electrons. It is also evidenced that the system exhibits both the conventional and inverse magnetocaloric effect depending on values of the applied magnetic field and temperature.

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“…Of particular interest is the investigation of the MCE in various one-dimensional (1D) quantum spin systems [4][5][6][7][8][9][10][11][12][13] or hybrid spin-electron models [14][15][16]. The reason is a possibility of obtaining the exact analytical or numerical results as well as a potential use of these models for the explanation of MCE data measured for real magnetic compounds.…”

Section: Introductionmentioning

confidence: 99%

Magnetic Grüneisen parameter and magnetocaloric properties of a coupled spin–electron double-tetrahedral chain

Gálisová

Strečka

2015

Physics Letters A

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Magnetocaloric effect in a double-tetrahedral chain, in which nodal lattice sites occupied by the localized Ising spins regularly alternate with three equivalent lattice sites available for mobile electrons, is exactly investigated by considering the one-third electron filling and the ferromagnetic Ising exchange interaction between the mobile electrons and their nearest Ising neighbours. The entropy and the magnetic Grüneisen parameter, which closely relate to the magnetocaloric effect, are exactly calculated in order to investigate the relation between the ground-state degeneracy and the cooling efficiency of the hybrid spin-electron system during the adiabatic demagnetization.

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Magnetocaloric Effect and Frustrations in One-Dimensional Magnets

Cited by 5 publications

References 12 publications

Investigation of magnetocaloric effect: Stoner approximation vs DMFT

Investigation of magnetocaloric effect: Stoner approximation vs DMFT

Ground-state and magnetocaloric properties of a coupled spin–electron double-tetrahedral chain (exact study at the half filling)

Magnetic Grüneisen parameter and magnetocaloric properties of a coupled spin–electron double-tetrahedral chain

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