Ambient pressure colossal magnetocaloric effect in Mn1−xCuxAs compounds

Rocco, D.L.; Campos, André Gambier; Carvalho, A. Magnus G.; Caron, L. G.; Coelho, A. A.; Gama, S.; Gandra, F. C. G.; Santos, A.O. dos; Cardoso, Lisandro Pavie; Ranke, P.J. von; Oliveira, N.A. de

doi:10.1063/1.2746074

Cited by 53 publications

(43 citation statements)

References 14 publications

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“…2(c), due to inadequate application of the Maxwell relation to the magnetization data, using the expression previously shown. The observed maximum value, −ΔS T,max = 138 J/kg·K for a field change of 6 T, is comparable to the literature values for Mn 1−x Fe x As [11] and Mn 1−x Cu x As [12]. On decreasing field, no spurious ΔS T peaks are obtained, since each demagnetization curve starts from a fully FM state in the phase transition region and only the data below 6 T are considered.…”

Section: Resultssupporting

confidence: 82%

“…The MCE of MnAs and its derivatives, with slight substitutions of Fe, Cu, and Cr for Mn, or Si and Sb for As [3,[10][11][12][13][14][15][16], have been extensively studied using magnetization data. As a result of an incorrect application of the Maxwell relation, some fallacious conclusions saying that the MnAs-based compounds exhibit "huge" or "colossal" MCE (|ΔS T,max | ∼ 300 J/kg·K) were made [11,12,15]. In this paper, we report on a giant MCE at room temperature (∼295 K) in Mn 0.99 Co 0.01 As, using three different methods, i.e., isothermal magnetization, heat capacity, and direct measurements.…”

Section: Introductionmentioning

confidence: 99%

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Comparative analysis of magnetic and caloric determinations of the magnetocaloric effect in Mn_0.99Co_0.01As

Wang

Palacios

Coelho

et al. 2014

EPJ Web of Conferences

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Abstract.The results from direct and indirect determinations of the magnetocaloric parameters of Mn 0.99 Co 0.01 As have been analyzed. The isothermal entropy change (ΔS T ) due to external magnetic field changes has been determined through direct measurements of the heat absorbed by the sample when the field is removed under isothermal conditions. It has also been calculated from isothermal magnetization and isofield heat capacity measurements. In addition to that, the adiabatic temperature change (ΔT S ) has been obtained from direct measurements and from isofield heat capacity measurements. The different results of both ΔS T and ΔT S are compared. Due to the presence of a first-order phase transition, the studied sample exhibits giant magnetocaloric effect at room temperature. The observed maximum values, −ΔS T,max = 32.1 J/kg·K and ΔT S ,max = 17.7 K for a field change from 0 to 6 T, suggest that the Co-doped MnAs compounds are promising candidates for the preparation of useful materials for magnetic refrigeration near room temperature.

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Section: Resultssupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Comparative analysis of magnetic and caloric determinations of the magnetocaloric effect in Mn_0.99Co_0.01As

Wang

Palacios

Coelho

et al. 2014

EPJ Web of Conferences

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“…[63] It was also observed in MnAs [64] and Mn 1-x Cu x As [65] under high pressure. It could be a general feature of the first-order phase transition because the finite temperature width of the phase transition.…”

Section: Mce In the Vicinity Of The First-order Phase Transitionmentioning

confidence: 80%

Recent Progress in Exploring Magnetocaloric Materials

et al. 2009

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Magnetic refrigeration based on the magnetocaloric effect (MCE) of materials is a potential technique that has prominet advantages over the currently used gas compression-expansion technique in the sense of its high efficiency and environment friendship. In this article, our recent progress in explorating effective MCE materials is reviewed with the emphasis on the MCE in the LaFe 13-x Si x -based alloys with a first order magnetic transition discovered by us. These alloys show large entropy changes in a wide temperature range near room temperature. Effects of magnetic rare-earth doping, interstitial atom, and high pressure on the MCE have been systematically studied. Special issues such as appropriate approaches to determining the MCE associated with the first-order magnetic transition, the depression of magnetic and thermal hystereses, and the key factors determining the magnetic exchange in alloys of this kind are discussed. The applicability of the giant MCE materials to the magnetic refrigeration near ambient temperature is evaluated. A brief review of other materials with significant MCE is also presented in the article.

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“…1 One way to tune the Curie temperature and thermal hysteresis of MnAs is to use atomic substitutions. However, the MnAs system exhibits a pronounced sensitivity to the lattice pressure 2 and applied field, 3 so that the atomic substitutions 4,5 tend to yield, leads to the large thermal and magnetic hysteresis. Here we explore a different approach, namely, the use of interstitial atoms to control the Curie temperature and MCE of MnAs.…”

Section: Introductionmentioning

confidence: 99%

Interstitial-nitrogen effect on phase transition and magnetocaloric effect in Mn(As,Si) (invited)

Cui¹,

Lv²,

Fu³

et al. 2010

Journal of Applied Physics

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"Interstitial-nitrogen effect on phase transition and magnetocaloric effect in Mn(As,Si) (invited)" (2010 The effect of interstitial nitrogen on the phase transition and magnetocaloric behavior of MnAs 1−x Si x N ␦ ͑x = 0.03, 0.06, and 0.09͒ is investigated. The interstitial nitrogen atoms cause the step-scanned x-ray diffraction peaks to shift toward lower angles and lower the Curie temperature, whereas silicon addition increases the Curie temperature to near room temperature. The thermal hysteresis is reduced to nearly 0 in MnAs 1−x Si x N ␦ , which is beneficial to practical applications. For a field change of 5 T, the largest magnetic entropy change and refrigerant capacity are 14.6 J kg −1 K −1 at 247 K and 360 J kg −1 , which is slightly higher than the entropy change in the parent alloy. Finally, we briefly discuss the occurrence and origin of the "virgin effect" in MnAs.

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Ambient pressure colossal magnetocaloric effect in Mn1−xCuxAs compounds

Cited by 53 publications

References 14 publications

Comparative analysis of magnetic and caloric determinations of the magnetocaloric effect in Mn_0.99Co_0.01As

Comparative analysis of magnetic and caloric determinations of the magnetocaloric effect in Mn_0.99Co_0.01As

Recent Progress in Exploring Magnetocaloric Materials

Interstitial-nitrogen effect on phase transition and magnetocaloric effect in Mn(As,Si) (invited)

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Ambient pressure colossal magnetocaloric effect in Mn1−xCuxAs compounds

Cited by 53 publications

References 14 publications

Comparative analysis of magnetic and caloric determinations of the magnetocaloric effect in Mn0.99Co0.01As

Comparative analysis of magnetic and caloric determinations of the magnetocaloric effect in Mn0.99Co0.01As

Recent Progress in Exploring Magnetocaloric Materials

Interstitial-nitrogen effect on phase transition and magnetocaloric effect in Mn(As,Si) (invited)

Contact Info

Product

Resources

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Comparative analysis of magnetic and caloric determinations of the magnetocaloric effect in Mn_0.99Co_0.01As

Comparative analysis of magnetic and caloric determinations of the magnetocaloric effect in Mn_0.99Co_0.01As