Magnetocaloric Effect in Intermetallic Compounds and Alloys

Roy, S. B.

doi:10.1016/b978-0-444-63291-3.00002-7

Cited by 27 publications

(12 citation statements)

References 339 publications

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“…5, the values for S max are shown in Table II. The values of S max are comparable with those other magnetocaloric alloys, e.g., the benchmark material Gd (8.3 Jkg −1 K −1 ) [47] and LaFe 10.6 Si 2.4 (5.85 Jkg −1 K −1 ) [48]. Although the entropy values are lower than some MnNiSi giant magnetocaloric alloys such as (MnNiSi) 0.62 (CoNiGe) 0.38 (40.3 Jkg −1 K −1 ) [43], (MnNiSi) 0.65 (Fe 2 Ge) 0.34 (57.6 Jkg −1 K −1 ) [21], and (MnNiSi) 0.46 (MnFeGe) 0.54 (40 Jkg −1 K −1 ) [14], the cost of synthesis of Mn 0.45 Fe 0.55 NiSi 1−y Sn y is much lower since Sn is much cheaper than that of Ge, Ga, or other rare-earth elements.…”

Section: Resultssupporting

confidence: 81%

Magnetocaloric Properties of Low-Cost Fe and Sn Substituted MnNiSi-Based Alloys Exhibiting a Magnetostructural Transition Near Room Temperature

Kunhappan

Ramanujan

2018

IEEE Trans. Magn.

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Section: Resultssupporting

confidence: 81%

Magnetocaloric Properties of Low-Cost Fe and Sn Substituted MnNiSi-Based Alloys Exhibiting a Magnetostructural Transition Near Room Temperature

Kunhappan

Ramanujan

2018

IEEE Trans. Magn.

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“…R-M based materials have played and continue to play a very important role for applied magnetic materials as well as basic scientific concepts in the field of heavy fermions [4][5][6], non-Fermi liquids [7], magnetic metals [5][6][7][8][9], magnetocaloric materials [10], etc. The R-site f electrons in intermetallic alloys often behave like localized electrons with a large magnetic moment.…”

Section: Introductionmentioning

confidence: 99%

Hard x-ray photoemission spectroscopy of the ferrimagnetic series Gd6(Mn1−xFex)23

et al. 2022

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We study the evolution of the electronic structure of the intermetallic series Gd 6 (Mn 1−x Fe x ) 23 , x = 0.0-0.75, which shows nonmonotonic ferrimagnetic ordering temperatures T C but with a systematic reduction of the total bulk magnetization upon increasing Fe content, x. We have carried out hard x-ray photoemission spectroscopy to elucidate the relation between electronic structure and properties of the series. The Gd 3d and Gd 4d corelevel spectra indicate trivalent Gd 3+ multiplets in the intermediate-coupling scheme with features due to L-S and j-J coupling. The Fe 2p core levels show asymmetric single peak metal-like spectra, while the Mn 2p core levels show asymmetric doublet peaks. The relative intensities of the Mn 2p doublets as a function of x indicate occupancy changes of distinct crystallographic sites associated with Mn up-spin and down-spin states. The valence band spectra identify the Gd 4 f states at high binding energies (∼7.4 eV). The Mn 3d states occur at the Fermi level and as a broad feature between 2 and 5 eV binding energy in Gd 6 Mn 23 . Upon substitution, the Fe 3d states show up as small shifts to higher binding energies compared to Mn 3d states. The Fe 3s and Mn 3s spectra show exchange split peaks, allowing an estimate of the Mn and Fe magnetic moments using a Van Vleck analysis, which also provides a quantification of occupancy changes with x. The overall results are consistent with the bulk net magnetization, indicating that Mn up-spin sites become Fe down-spin sites on substitution, while the nonmonotonic T C originates in a change from Mn sublattice to Fe sublattice derived ordering.

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“…Magnetocaloric refrigeration has been proposed as a promising tool for more energy efficient cooling. [1][2][3][4][5][6] One of the materials under investigation is the Heusler alloy Ni-Mn-Ga-Co. This compound exhibits an inverse magnetocaloric effect around room temperature due to a first order phase transition from a ferromagnetic austenite to a weak magnetic martensite with an entropy change of up to 17 J/(kgK) in a magnetic field of 5 T. 7 However, one drawback of a first order transition is the narrow usable temperature range as the transition temperature of the material has to span the entire working region of the cooling device.…”

Section: Introductionmentioning

confidence: 99%

Reversible tuning of magnetocaloric Ni-Mn-Ga-Co films on ferroelectric PMN-PT substrates

Schleicher

Niemann

Schwabe

et al. 2017

Sci Rep

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Tuning functional properties of thin caloric films by mechanical stress is currently of high interest. In particular, a controllable magnetisation or transition temperature is desired for improved usability in magnetocaloric devices. Here, we present results of epitaxial magnetocaloric Ni-Mn-Ga-Co thin films on ferroelectric Pb(Mg1/3Nb2/3)0.72Ti0.28O3 (PMN-PT) substrates. Utilizing X-ray diffraction measurements, we demonstrate that the strain induced in the substrate by application of an electric field can be transferred to the thin film, resulting in a change of the lattice parameters. We examined the consequences of this strain on the magnetic properties of the thin film by temperature- and electric field-dependent measurements. We did not observe a change of martensitic transformation temperature but a reversible change of magnetisation within the austenitic state, which we attribute to the intrinsic magnetic instability of this metamagnetic Heusler alloy. We demonstrate an electric field-controlled entropy change of about 31 % of the magnetocaloric effect - without any hysteresis.

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Magnetocaloric Effect in Intermetallic Compounds and Alloys

Cited by 27 publications

References 339 publications

Magnetocaloric Properties of Low-Cost Fe and Sn Substituted MnNiSi-Based Alloys Exhibiting a Magnetostructural Transition Near Room Temperature

Magnetocaloric Properties of Low-Cost Fe and Sn Substituted MnNiSi-Based Alloys Exhibiting a Magnetostructural Transition Near Room Temperature

Hard x-ray photoemission spectroscopy of the ferrimagnetic series Gd6(Mn1−xFex)23

Reversible tuning of magnetocaloric Ni-Mn-Ga-Co films on ferroelectric PMN-PT substrates

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