Magnetic couplings and magnetocaloric effect in the GdTX (T=Sc, Ti, Co, Fe; X=Si, Ge) compounds

García, D. J.; Vildosola, V.; Cornaglia, P. S.

doi:10.1088/1361-648x/ab7e5a

Cited by 10 publications

(6 citation statements)

References 45 publications

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“…Compound-specific results obtained in the context of MCE in the density functional approach are of high value but it can be difficult to derive any qualitative and unbiased conclusions from these investigations 3, [55][56][57] . However, the model-based approach used in the paper, which ignores any specific features of the density of states, captures the fundamentals about metals and allows for a completely general description of the phase separation in a first order magnetic phase transition and how it impacts MCE.…”

Section: Discussionmentioning

confidence: 99%

Emerging mechanisms of magnetocaloric effect in phase-separated metals

Ivchenko,

Igoshev

2021

Preprint

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We present a study of the magnetocaloric effect in metallic systems exhibiting first order magnetic transitions and focus on consequences of magnetic phase separation. We account for ferrimagnetic, ferromagnetic and Neel antiferromagnetic order. Based on the archetypal Hubbard model being treated within the mean-field approximation, we provide and explore its implications on the fieldinduced entropy change in metallic system with phase separation. Chosen framework allows us to properly analyze phase volumes' dependence on parameters of phase-separated (PS) system.Moreover, an account for phase separation boundaries as functions of magnetic field provides a natural splitting of the PS region, where each subregion corresponds to a different temperature dependence of entropy change: moving from one subregion to the other produces a kink, followed by a strong linear growth of entropy change. We encounter a second order magnetic transition from paramagnetic to antiferromagnetic phase in PS region that occurs for particular parameter values. Despite the fact that both phases have zero total magnetization, the transition has a strong impact on entropy change.

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Section: Discussionmentioning

confidence: 99%

Emerging mechanisms of magnetocaloric effect in phase-separated metals

Ivchenko,

Igoshev

2021

Preprint

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“…The phase diagram of Fig. 2 was constructed through classical Monte Carlo numerical simulations of the magnetic Hamiltonian, considering the large J = 7/2 magnetic moments of the Eu +2 ions as classical [19][20][21][22] . It presents four phases which result from the competition between the exchange interactions and the easy-axis anisotropy.…”

Section: Monte Carlo Phase Diagrammentioning

confidence: 99%

“…Ref. 22). The isothermal entropy change for a reversible change in the magnetization can also be obtained integrating a Maxwell relation.…”

Section: Magnetocaloric Effectmentioning

confidence: 99%

Large magnetocaloric effect in the frustrated antiferromagnet EuIr$_2$P$_2$

García¹,

Franco²,

Cornaglia³

2021

Preprint

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We present a theoretical analysis of the magnetocaloric effect in the frustrated antiferromagnet EuIr2P2. Based on a magnetic Hamiltonian with parameters estimated using total energy density functional theory calculations, we perform classical Monte Carlo simulations to obtain the magnetocaloric effect as a function of the temperature and the external magnetic field. We find a large magnetic entropy change ∆S max M ∼ 5.14 J kg −1 K −1 at T = 2.45K for a moderate change in the external magnetic field ∆H = 1.2 Tesla. Magnetic frustration in EuIr2P2 leads to a rich phase diagram with a first order (spin-flop) transition between two antiferromagnetic phases and a continuous transition between a non-collinear antiferromagnetic phase and a high entropy collinear antiferromagnet. A paramagnetic phase for high fields or temperatures completes the phase diagram. A phenomenological Landau functional analysis suggests that the four phases meet at a multicritical point (Tm, Hm), and provides a simplified description of the phase diagram and of the magnetocaloric effect. The highest value of ∆SM is obtained for a temperature T ∼ Tm but it persists with similar values for a broad range of temperatures T Tm.

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“…Some models analyze the MCE using different methods. Recently, the properties of MCE were studied by several theoretical methods, namely, mean-field theory (MFT) [20][21][22][23][24][25][26][27], effective-field theory (EFT) [28][29][30][31][32][33], Monte Carlo (MC) simulation [34][35][36][37][38][39] and first-principles calculations [40][41][42].…”

Section: Introductionmentioning

confidence: 99%

Theoretical analysis of magnetic properties and the magnetocaloric effect using the Blume-Capel model

Oliveira¹,

Morais²,

Santos³

et al. 2022

Condens. Matter Phys.

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This work investigates the magnetic properties and the magnetocaloric effect in the spin-1 Blume-Capel model. The study was carried out using the mean-field theory from the Bogoliubov inequality to obtain the expressions of free energy, magnetization and entropy. The magnetocaloric effect was calculated from the variation of the entropy obtained by the mean-field theory. Due to the dependence on the external magnetic field and the anisotropy included in the model, the results for the magnetocaloric effect provided the system with first-order and continuous phase transitions. To ensure the results, the Maxwell relations were used in the intervals where the model presents continuous variations in magnetization and the Clausius-Clapeyron equation in the intervals where the model presents discontinuity in the magnetization. The methods and models for the analysis of a magnetic entropy change and first-order and continuous magnetic phase transitions, such as mean-field theory and the Blume-Capel model, are useful tools in understanding the nature of the magnetocaloric effect and its physical relevance.

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Magnetic couplings and magnetocaloric effect in the GdTX (T=Sc, Ti, Co, Fe; X=Si, Ge) compounds

Cited by 10 publications

References 45 publications

Emerging mechanisms of magnetocaloric effect in phase-separated metals

Emerging mechanisms of magnetocaloric effect in phase-separated metals

Large magnetocaloric effect in the frustrated antiferromagnet EuIr$_2$P$_2$

Theoretical analysis of magnetic properties and the magnetocaloric effect using the Blume-Capel model

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