Giant adiabatic temperature change in FeRh alloys evidenced by direct measurements under cyclic conditions

Chirkova, I. М.; Skokov, Konstantin P.; Schultz, L.; Баранов, Н. В.; Gutfleisch, Oliver; Woodcock, T.G.

doi:10.1016/j.actamat.2015.11.054

Cited by 159 publications

(111 citation statements)

References 26 publications

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“…, which is close to the experimentally reported values of the total entropy change obtained in field-, pressure-, and temperature-induced transitions, ranging from 12 J kg [26,30,33,38,56,57,116]. Our S vib+el is a sum of nearly equal parts of the electronic entropy and the lattice contribution of Rh.…”

Section: Thermodynamic Stability From Quasiharmonic Calculationssupporting

confidence: 64%

“…Recently, also the giant magnetocaloric effect (MCE) of B2 FeRh shifted back into the scientific focus, since FeRh has one of the highest adiabatic temperature changes of all known materials [26][27][28][29][30][31], which in addition is accompanied by large elasto-and barocaloric effects [32][33][34]. However, the transition suffers from a large hysteresis and a high sensitivity to stoichiometry and antisite defects [35].…”

Section: Published By the American Physical Society Under The Terms Omentioning

confidence: 99%

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Impact of lattice dynamics on the phase stability of metamagnetic FeRh: Bulk and thin films

et al. 2016

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We present phonon dispersions, element-resolved vibrational density of states (VDOS) and corresponding thermodynamic properties obtained by a combination of density functional theory (DFT) and nuclear resonant inelastic x-ray scattering (NRIXS) across the metamagnetic transition of B2 FeRh in the bulk material and thin epitaxial films. We see distinct differences in the VDOS of the antiferromagnetic (AF) and ferromagnetic (FM) phases, which provide a microscopic proof of strong spin-phonon coupling in FeRh. The FM VDOS exhibits a particular sensitivity to the slight tetragonal distortions present in epitaxial films, which is not encountered in the AF phase. This results in a notable change in lattice entropy, which is important for the comparison between thin film and bulk results. Our calculations confirm the recently reported lattice instability in the AF phase. The imaginary frequencies at the X point depend critically on the Fe magnetic moment and atomic volume. Analyzing these nonvibrational modes leads to the discovery of a stable monoclinic ground-state structure, which is robustly predicted from DFT but not verified in our thin film experiments. Specific heat, entropy, and free energy calculated within the quasiharmonic approximation suggest that the new phase is possibly suppressed because of its relatively smaller lattice entropy. In the bulk phase, lattice vibrations contribute with the same sign and in similar magnitude to the isostructural AF-FM phase transition as excitations of the electronic and magnetic subsystems demonstrating that lattice degrees of freedom need to be included in thermodynamic modeling.

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Section: Thermodynamic Stability From Quasiharmonic Calculationssupporting

confidence: 64%

Section: Published By the American Physical Society Under The Terms Omentioning

confidence: 99%

Impact of lattice dynamics on the phase stability of metamagnetic FeRh: Bulk and thin films

et al. 2016

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“…Figure shows the magnetocaloric effect of the alloy Ni 45 Co 5 Mn 32 Cr 5 In 13 with an adiabatic temperature change of nearly 10 K . This is a record value for Heusler alloys and is close to the Δ T ad =12.9 K value of Fe–Rh and 9.2 K for Fe 49 Rh 51 upon the first application of a magnetic field of Δ μ 0 H =1.9 T, which remains as high as 6.2 K during cycling in an alternated field of the same magnitude . It has been shown that a magnetic state change of Rh between antiferromagnetism (with a Rh moment of 0 μ B ) and ferromagnetism (≈0.9 μ B ), accompanied by a significant change in electronic structure, combine as the main origin of the metamagnetic transition .…”

Section: Magnetostructural Phase Transition Of Rapidly Quenched Heuslsupporting

confidence: 54%

Properties and Decomposition of Heusler Alloys

et al. 2018

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Martensitic transformations of rapidly quenched and less‐rapidly cooled Heusler alloys of type Ni–Mn–X with X=Ga, In, and Sn are investigated by ab initio calculations. For alloys rapidly cooled from 1173 K, we obtain the well‐known magnetocaloric properties near the magnetocaloric phase transition. For the less‐rapidly cooled alloys with secondary heat treatment these magnetocaloric properties start to change considerably, because each alloy transforms during temper‐annealing into a dual‐phase composite alloy. These two phases are identified to be cubic stoichiometric Ni2MnX and tetragonal disordered NiMn.

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“…Сплавы на основе Fe−Rh являются перспективными для технологии магнитного охлаждения и имеют рекорд-но большие значения магнитокалорического эффекта на сегодняшний день [4][5][6][7][8][9]. В работах [4][5] магни-токалорические свойства сплавов Fe 51 Rh 49 измерялись прямым методом.…”

Section: Introductionunclassified

“…В работах [4][5] магни-токалорические свойства сплавов Fe 51 Rh 49 измерялись прямым методом. Адиабатическое изменение темпера-туры сплава Fe 51 Rh 49 составило 13 K в изменяющемся магнитном поле до 2 T. Фазовый переход наблюдается при температуре, близкой к 310 K. Хорошо известно, что магнитный порядок в соединениях Fe−Rh сильно зави-сит от концентрации элементов.…”

Section: Introductionunclassified

Исследование структуры и магнитных свойств сплавов Fe-=SUB=-8-=/SUB=-Rh-=SUB=-8-x-=/SUB=-Z-=SUB=-x-=/SUB=- (Z=Mn, Pt, Co; x=1, 2 и 3) первопринципными методами

Pavlukhina¹,

Соколовский²,

Buchelnikov³

et al. 2018

Физика Твердого Тела

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The results of first-principles studies of the structure and magnetic properties of Fe–Rh–Z alloys conducted using the VASP package are reported. The magnetic moments and lattice parameters are determined, and the possibility of existence of stable tetragonal distortions in Fe–Rh–Z alloys with various magnetic configurations set by the level of doping with Mn, Pt, and Co is examined. It is demonstrated that the equilibrium lattice parameter and the type of magnetic ordering change with the concentration of the third element.

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Giant adiabatic temperature change in FeRh alloys evidenced by direct measurements under cyclic conditions

Cited by 159 publications

References 26 publications

Impact of lattice dynamics on the phase stability of metamagnetic FeRh: Bulk and thin films

Impact of lattice dynamics on the phase stability of metamagnetic FeRh: Bulk and thin films

Properties and Decomposition of Heusler Alloys

Исследование структуры и магнитных свойств сплавов Fe-=SUB=-8-=/SUB=-Rh-=SUB=-8-x-=/SUB=-Z-=SUB=-x-=/SUB=- (Z=Mn, Pt, Co; x=1, 2 и 3) первопринципными методами

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