On the determination of the magnetic entropy change in materials with first-order transitions

Caron, L. G.; Ou, Z.Q.; Nguyen, Tin T.; Thanh, D.T. Cam; Tegus, O.; Brück, E.

doi:10.1016/j.jmmm.2009.06.086

Cited by 472 publications

(244 citation statements)

References 20 publications

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“…From these data, the magneticfi eld-induced entropy change was numerically computed, taking into account the procedures described in (ref. 24), to avoid undesired overestimated values. Specifi c heat was measured using a modulated diff erential scanning calorimeter.…”

Section: Methodsmentioning

confidence: 99%

Inverse barocaloric effect in the giant magnetocaloric La–Fe–Si–Co compound

et al. 2011

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Application of hydrostatic pressure under adiabatic conditions causes a change in temperature in any substance. This effect is known as the barocaloric effect and the vast majority of materials heat up when adiabatically squeezed, and they cool down when pressure is released (conventional barocaloric effect). There are, however, materials exhibiting an inverse barocaloric effect: they cool when pressure is applied, and they warm when it is released. Materials exhibiting the inverse barocaloric effect are rather uncommon. Here we report an inverse barocaloric effect in the intermetallic compound La-Fe-Co-Si, which is one of the most promising candidates for magnetic refrigeration through its giant magnetocaloric effect. We have found that application of a pressure of only 1 kbar causes a temperature change of about 1.5 K. This value is larger than the magnetocaloric effect in this compound for magnetic fi elds that are available with permanent magnets.

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Section: Methodsmentioning

confidence: 99%

Inverse barocaloric effect in the giant magnetocaloric La–Fe–Si–Co compound

et al. 2011

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“…To accurately derive the magnetic-entropy changes (∆S m ) at magnetostructural transitions with thermal hysteresis, the so-called loop process method 49 was adopted to get the isothermal magnetization curves. The isothermal M(B) curves were measured in fields of up to 5 T upon cooling with a temperature interval of 2 K. Before each isothermal magnetization, the samples were all the way heated up to the complete PM austenite region (100 K away from the magnetostructural transitions) with heating rate of 5 K min − 1 to eliminate the history-dependent magnetic states and then cooled back to the targeted measurement temperature points.…”

Section: Magnetic Measurementsmentioning

confidence: 99%

Stable magnetostructural coupling with tunable magnetoresponsive effects in hexagonal ferromagnets

et al. 2012

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The magnetostructural coupling between the structural and the magnetic transition has a crucial role in magnetoresponsive effects in a martensitic-transition system. A combination of various magnetoresponsive effects based on this coupling may facilitate the multifunctional applications of a host material. Here we demonstrate the feasibility of obtaining a stable magnetostructural coupling over a broad temperature window from 350 to 70 K, in combination with tunable magnetoresponsive effects, in mnniGe:Fe alloys. The alloy exhibits a magneticfield-induced martensitic transition from paramagnetic austenite to ferromagnetic martensite. The results indicate that stable magnetostructural coupling is accessible in hexagonal phasetransition systems to attain the magnetoresponsive effects with broad tunability.

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“…32 For the case T ref >T c , by re-arranging equation (1) and setting ΔS Max =ΔS HC for T comp (where T comp is a temperature chosen for the comparison such that T comp ≪ T c and taken here as 110 K) the offset between the two measurements, denoted here as K(H 1 ,H 2 ), is found, as described by equation…”

Section: Indirect Determination Of Latent Heatmentioning

confidence: 99%

Identifying the critical point of the weakly first-order itinerant magnet DyCo2with complementary magnetization and calorimetric measurements

et al. 2013

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We examine the character of the itinerant magnetic transition of DyCo 2 by different calorimetric methods, thereby separating the heat capacity and latent heat contributions to the entropyallowing direct comparison to other itinerant electron metamagnetic systems. The heat capacity exhibits a large lambda-like peak at the ferrimagnetic ordering phase transition, a signature that is remarkably similar to La(Fe,Si) 13 where it is attributed to giant spin fluctuations. Using calorimetric measurements we also determine the point at which the phase transition ceases to be first order: the critical field, µ 0 H crit = 0.4±0.1 T and T crit = 138.5±0.5 K, and we compare these to values obtained from analysis of magnetization by application of the Shimizu inequality for itinerant electron metamagnetism. Good agreement is found between these independent measurements, thus establishing the phase diagram and critical point with some confidence. In addition we find that the often-used Banerjee criterion may not be suitable for determination of first order behavior in itinerant magnet systems. PACS number(s):

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On the determination of the magnetic entropy change in materials with first-order transitions

Cited by 472 publications

References 20 publications

Inverse barocaloric effect in the giant magnetocaloric La–Fe–Si–Co compound

Inverse barocaloric effect in the giant magnetocaloric La–Fe–Si–Co compound

Stable magnetostructural coupling with tunable magnetoresponsive effects in hexagonal ferromagnets

Identifying the critical point of the weakly first-order itinerant magnet DyCo2with complementary magnetization and calorimetric measurements

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