The Magnetocaloric Effect and Magnetic Refrigeration Near Room Temperature: Materials and Models

Franco, V.; Blázquez, J.S.; Ingale, Babita; Conde, A.

doi:10.1146/annurev-matsci-062910-100356

Cited by 1,028 publications

(479 citation statements)

References 214 publications

(189 reference statements)

Supporting

Mentioning

466

Contrasting

Unclassified

Order By: Relevance

“…The magnitude of ∆S M decreases with increasing nickel content, while the refrigerant capacity (RC F W HM ), a measure of the heat that may be transferred between the hot and cold reservoirs, is maximized for the x = 0.75 composition. 2 Here, we demonstrate a materials system with significant ∆S M over a large range of transition temperatures useful for thermomagnetic power generation. These results may prove useful in other well-studied Heusler systems which behave similarly.…”

Section: Introductionmentioning

confidence: 90%

“…The product of the FWHM and the peak ∆S M yields the refrigerant capacity (RC). 2 While the magnitude of ∆S M decreases as x increases, the broadening of the transition leads to an increase in the refrigerant capacity with a maximum at x = 0.75. The structure in the ∆S M curve for x = 1 is likely an artifact associated with fitting the derivatives of a the very broad magnetic transition, or may be due to small amounts of inhomogeneity in that sample.…”

Section: Magnetic Characterizationmentioning

confidence: 96%

“…Of primary interest are materials with transitions near room temperature, which can be used for residential and commercial refrigeration. 1,2 Materials displaying a large magnetocaloric effect at high temperatures may have uses in recovery of waste heat via thermomagnetic power generation, while low temperature materials may be used for gas liquefaction. 3,4 There is currently a lack of information on the magnetocaloric properties of materials with transition temperatures above room temperature, which is a hindrance to the study of thermomagnetic generators for waste heat recovery.…”

Section: Introductionmentioning

confidence: 99%

“…6,[19][20][21] The phase transition involves a significant volume change, which poses a challenge for engineering a device that must withstand continuous, rapid cycling. 2,22 This challenge was acknowledged by Singh et al, who explored the system Mn 1+x Ni 2 In 1−x (x < 0.4) aiming to increase ∆S M by increasing magnetization without driving a first-order transition. As x increases, some of the Z site is replaced by Mn, increasing the overall moment and leading to an improved ∆S M .…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Tuning the magnetocaloric response in half-Heusler/Heusler MnNi1+xSb solid solutions

Levin

Bocarsly

Wyckoff

et al. 2017

Phys. Rev. Materials

View full text Add to dashboard Cite

Materials with a large magnetocaloric response are associated with a temperature change upon the application of a magnetic field, and are of interest for applications in magnetic refrigeration and thermomagnetic power generation. The usual metric of this response is the gravimetric isothermal entropy change ∆SM . The use of a simple proxy for the ∆SM that is based on density functional theory (DFT) calculations of the magnetic electronic structure, suggests that half-Heusler MnNiSb should be a better magnetocaloric than the corresponding Heusler compound MnNi2Sb. Guided by this observation, we present a study of MnNi1+xSb (x = 0, 0.25, 0.5, 0.75, 1.0) to evaluate relevant structural and magnetic properties. DFT stability calculations suggest that the addition of Ni takes place at a symmetrically distinct Ni site in the half-Heusler structure, and support the observation using synchrotron X-ray diffraction of a homogeneous solid solution between the half-Heusler and Heusler endmembers. There is a maximum in the saturation magnetization at x = 0.5, and the Curie temperature systematically decreases with increasing x. ∆SM for a maximum magnetic field change of ∆H = 5 T monotonically decreases in magnitude from −2.93 J kg −1 K −1 in the half-Heusler to −1.35 J kg −1 K −1 in the Heusler compound. The concurrent broadening of the magnetic transition results in a maximum in the refrigerant capacity at x = 0.75. The Curie temperature of this system is highly tunable between 350 K and 750 K, making it ideal for low grade waste heat recovery via thermomagnetic power generation. The increase in ∆SM with decreasing x may be extendable to other MnNi2Z Heusler systems that are currently under investigation for use in magnetocaloric refrigeration applications.

show abstract

Section: Introductionmentioning

confidence: 90%

Section: Magnetic Characterizationmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Tuning the magnetocaloric response in half-Heusler/Heusler MnNi1+xSb solid solutions

Levin

Bocarsly

Wyckoff

et al. 2017

Phys. Rev. Materials

View full text Add to dashboard Cite

show abstract

“…Magnetic refrigeration is an emerging, environmentally-friendly technology based upon materials that exhibit a magnetocaloric effect [1][2][3][4]. The class of materials consisting of the rare earth metal Gd, and its alloys or compounds with the post-transition elements Si and Ge, is particularly promising because some of its members exhibit a giant magnetocaloric transition near room temperature [5].…”

Section: Introductionmentioning

confidence: 99%

Structure of the clean Gd₅Ge₄(010) surface

Yuen¹,

Miller²,

Lei³

et al. 2013

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

We have characterized the (010) surface of Gd5Ge4 using scanning tunneling microscopy (STM) and x-ray photoelectron spectroscopy. Data from different samples have the following features in common: (1) the surface composition equals the bulk composition to within 5 at.%, both after ion etching and after annealing at temperatures of 400-1200 K; and (2) the surface exhibits terraces of two types. The height of the steps between similar terraces corresponds well to the separation between equivalent layers along the h010i direction in the bulk structure. Density functional theory (DFT) shows that the surface energy of the (0001) plane of hexagonal close-packed Gd is lower than that of the (111) plane of diamond-type Ge, suggesting that surfaces of Gd5Ge4 (for comparable density) should be rich in Gd. Indeed, DFT shows that among the bulk terminations of Gd5Ge4, a pure Ge termination is not favored. Each of the three remaining terminations (two pure Gd and one mixed, Gd-Ge) has its minimum surface energy in a different range of the possible Gd chemical potentials, indicating that different terminations may be stable under different conditions. DFT shows that the heights of the steps between dissimilar terraces, measured in STM, are consistent with the two pure Gd terminations. Abstract.We have characterized the (010) surface of Gd5Ge4 using scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy. Data from different samples have the following features in common: (1) Surface composition equals bulk composition to within 5 atomic %, both after ion etching and after annealing at temperatures of 400 K to 1200 K; and (2) The surface exhibits two types of terraces.Step heights between similar terraces correspond well to the separation between equivalent layers along the <010> direction in the bulk structure. Density functional theory (DFT) shows that the surface energy of the (0001) plane of hcp Gd is lower than that of the (111) plane of diamond-type Ge, suggesting that surfaces of Gd5Ge4 (for comparable density) should be Gd-rich. Indeed, among the bulk terminations of Gd5Ge4, DFT shows that a pure Ge termination is not favored. The three remaining terminations (two pure Gd and one mixed DFT shows that step heights between dissimilar terraces, measured in STM, are consistent with the two pure Gd terminations.

show abstract

Magnetic Cooling: Principles, Materials, and Operation

Hepburn

2014

Wiley Encyclopedia of Electrical and Electronics Engineering

View full text Add to dashboard Cite

The application and subsequent removal of a magnetic field causes cooling in certain materials, known as the magnetocaloric effect (MCE), and is the basis for magnetic refrigeration. This method of cooling was originally used to provide temperatures below 1 Kelvin but due to the discovery of materials exhibiting the MCE near room temperature, magnetic refrigeration as an alternative to conventional compressed gas refrigeration has emerged as a very active research field. Magnetic refrigeration is an efficient reversible refrigeration process and thus is attractive as an alternative to less efficient conventional room temperature refrigeration methods. The mechanism by which cooling is achieved is either by the magnetic field interaction with electrons, for temperatures greater than a few millikelvin or via the atomic nucleus for temperature lower than a millikelvin. The classical form of magnetic refrigeration utilizing electron cooling via the MCE is the adiabatic demagnetization refrigerator and the nuclear demagnetization refrigerator when utilizing the atomic nucleus for cooling.

show abstract

The Magnetocaloric Effect and Magnetic Refrigeration Near Room Temperature: Materials and Models

Cited by 1,028 publications

References 214 publications

Tuning the magnetocaloric response in half-Heusler/Heusler MnNi1+xSb solid solutions

Tuning the magnetocaloric response in half-Heusler/Heusler MnNi1+xSb solid solutions

Structure of the clean Gd₅Ge₄(010) surface

Magnetic Cooling: Principles, Materials, and Operation

Contact Info

Product

Resources

About

The Magnetocaloric Effect and Magnetic Refrigeration Near Room Temperature: Materials and Models

Cited by 1,028 publications

References 214 publications

Tuning the magnetocaloric response in half-Heusler/Heusler MnNi1+xSb solid solutions

Tuning the magnetocaloric response in half-Heusler/Heusler MnNi1+xSb solid solutions

Structure of the clean Gd5Ge4(010) surface

Magnetic Cooling: Principles, Materials, and Operation

Contact Info

Product

Resources

About

Structure of the clean Gd₅Ge₄(010) surface