Magnetocaloric materials and the optimization of cooling power density

Wikus, P.; Canavan, Edgar R.; Heine, Sarah Trowbridge; Matsumoto, Koichí; Numazawa, Takenori

doi:10.1016/j.cryogenics.2014.04.005

Cited by 54 publications

(40 citation statements)

References 58 publications

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“…This alloy can show a large MCE, e.g., S T −10 J kg −1 K −1 for B = 0-5 T, though only for a narrow temperature range near T C . Recently, the polarization of a rare-earth atom by the exchange field produced by a transition metal has revealed itself as an interesting mechanism to increase the MCE over a much wider T span, as reported for GdCrO 4 [8,9].…”

Section: Introductionmentioning

confidence: 87%

Magnetic structures and magnetocaloric effect in RVO4(R=Gd, Nd)

et al. 2018

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We report the magnetic properties and magnetic structure of the zircon-type compound GdVO 4 , together with the magnetic structure of the isostructural NdVO 4 . At T 2.5 K, GdVO 4 undergoes a phase transition to antiferromagnetic G z , driven mainly by the exchange interactions, while the magnetic anisotropy and dipolar interactions are minor contributions. Near the liquid-helium boiling temperature, the magnetocaloric effect of GdVO 4 is nearly as large as that of the structurally closely related GdPO 4 . It is noteworthy that GdVO 4 has been recently proposed as a good passive regenerator in Gifford-McMahon cryocoolers, since adding a magnetizationdemagnetization stage to the cryocooler refrigeration cycle would increase its efficiency for liquefying helium. NdVO 4 is a canted G z -type antiferromagnet and shows enhancement of the magnetic reflections in neutron diffraction below ca. 500 mK, due to the polarization of the Nd nuclei by the hyperfine field.

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Section: Introductionmentioning

confidence: 87%

Magnetic structures and magnetocaloric effect in RVO4(R=Gd, Nd)

et al. 2018

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“…1 and 2, requiring high magnetic-ion density and large spin quantum number, both of which make the magnetic ordering temperature rather higher. Compromising the two contradicting requirements, we select GGG as the magnetic refrigerant in the present setup 17 . Availability of single crystals is also an advantage of GGG, ensuring high thermal conductivity necessary to efficiently cool the low-temperature part.…”

Section: Instrument Design and Operationmentioning

confidence: 99%

“…ADR is based on the magnetocaloric effect of paramagnetic materials, called magnetic refrigerants. In classical thermodynamics, the adiabatic temperature change due to the magnetocaloric effect is given as 17 :…”

Section: Introductionmentioning

confidence: 99%

Tiny adiabatic-demagnetization refrigerator for a commercial superconducting quantum interference device magnetometer

Sato

Okuyama

Kimura

2016

Review of Scientific Instruments

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A tiny adiabatic-demagnetization refrigerator (T-ADR) has been developed for a commercial superconducting quantum interference device magnetometer [Magnetic Property Measurement System (MPMS) from Quantum Design]. The whole T-ADR system is fit in a cylindrical space of diameter 8.5 mm and length 250 mm, and can be inserted into the narrow sample tube of MPMS. A sorption pump is self-contained in T-ADR, and hence no complex gas handling system is necessary. With the single crystalline GdGaO garnet (∼2 g) used as a magnetic refrigerant, the routinely achievable lowest temperature is ∼0.56 K. The lower detection limit for a magnetization anomaly is ∼1 × 10 emu, estimated from fluctuation of the measured magnetization. The background level is ∼5 × 10 emu below 2 K at H = 100 Oe, which is largely attributable to a contaminating paramagnetic signal from the magnetic refrigerant.

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“…[8,9] Novel proposals have been made to increase the efficiency, including a multistep process to collect the wasted energies, [9] which in turn will increase the cost and efficiency, and the aim close to 0.5 is still a great obstacle for the traditional gas compress-expansion processes.Magnetic refrigeration using the magnetocaloric effect (MCE) of a magnetic material is, in principle, a most efficient way for LH 2 because the MCE involving the spin-spin interaction can operate at ideal Carnot circle and the entropy density of an MC material is generally thousands times more than that of the gaseous form. [10][11][12] Adiabatic demagnetization refrigeration (ADR) can achieve above 90% of the Carnot efficiency with a limited temperature span, whereas the active magnetic regenerate refrigerator (AMR) designed to give enough temperature spans did not realize the estimated efficiency yet. One of the main problems for the decrease in the efficiency of various prototypes of the MC refrigerators is that they use a number of stages to cover enough temperature spans due to the lack of a single suitable MC material.…”

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confidence: 99%

Enhancing the Magnetocaloric Effect of a Paramagnet to above Liquid Hydrogen Temperature

2019

Energy Tech

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Liquid hydrogen (LH2) is one of the most efficient ways for storing and transporting the H2 energy in hydrogen economy. Magnetic refrigeration using the magnetocaloric effect (MCE) is the preferable means to liquify H2 since the adiabatic demagnetization process can approach 100% of carnot efficiency. In practice, mainly due to the lack of single material that covers enough temperature span, the efficiencies of the prototypes of magnetic refrigerators are still far below the economic viable threshold (50%). Based on a theoretical analysis on the single ion anisotropy of Tb3+‐containing materials, it is found experimentally that MCE can be 100% enhanced for a model crystal LiCaTb5(BO3)6 (LCTB) at 20.2 K over the practical magnetic cooling medium Gd3Ga5O13 (GGG) for the cryogenic temperatures, and more importantly the enhancement covers a range of at least 15–40 K in a typical field change of 6 T.

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Magnetocaloric materials and the optimization of cooling power density

Cited by 54 publications

References 58 publications

Magnetic structures and magnetocaloric effect in RVO4(R=Gd, Nd)

Magnetic structures and magnetocaloric effect in RVO4(R=Gd, Nd)

Tiny adiabatic-demagnetization refrigerator for a commercial superconducting quantum interference device magnetometer

Enhancing the Magnetocaloric Effect of a Paramagnet to above Liquid Hydrogen Temperature

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