Reversible solid-state hydrogen-pump driven by magnetostructural transformation in the prototype system La(Fe,Si)13H<i>y</i>

Krautz, Maria; Moore, James D.; Skokov, Konstantin P.; Liu, Jian; Teixeira, Cristiano da Silva; Schäfer, Rudolf; Schultz, L.; Gutfleisch, Oliver

doi:10.1063/1.4759438

Cited by 48 publications

(34 citation statements)

References 32 publications

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“…Between annealing protocols, the sample was heated well above T C , typically to 390 K at 1 K/min and subsequently cooled down 21 to reverse any previous diffusion and to ensure that the hydrogen is uniformly distributed as at this temperature the recombination speed is in the range of minutes. 17 We hereafter call this the recombined state. The sample was cooled down to the temperature of interest, T A , and kept at T A for a period of time lasting between several hours and 3 days.…”

Section: Methodsmentioning

confidence: 99%

“…Details of the sample preparation are given elsewhere. 17 Magnetization measurements were performed using a commercial vibrating sample magnetometer (Quantum Design PPMS). Since the magnetic state of the sample strongly depends on its annealing history, the latter will be given in detail.…”

Section: Methodsmentioning

confidence: 99%

“…However, it has recently been discovered that the single, sharp magnetic phase transition of partially hydrogenated LaFe 13−x Si x H y (y < 1.75) is unstable. [16][17][18] The transition has been seen to split into two separate transitions with distinctive T C s when the material is kept close to its unsplit phase transition temperature, T C0 . Such a split of T C implies that a diffusion of hydrogen atoms has taken place within the material, leading to hydrogen segregation and hence an inhomogeneous distribution of T C s.…”

Section: Introductionmentioning

confidence: 99%

“…In the simplest model, diffusion of the hydrogen atoms would take place from the lower volume PM phase to the higher volume FM phase 16,17 since the ferromagnetic unit cell volume is about 1 to 2% larger while the symmetry of the cubic crystal structure is preserved. 5,19,20 As a result, the T C of the PM regions T C1 decreases while the T C of the FM regions T C2 increases, stabilizing the resulting states and eventually leading to the appearance of two distinctive magnetic phase transitions.…”

Section: Introductionmentioning

confidence: 99%

“…It has been reported that the time for this thermally activated recombination ranges from days to minutes as the recombination temperature is increased. 17,18 While the dynamics of recombination have been investigated, little has been done to investigate the timescale of the transition splitting process which is of great relevance to the efficiency of cooling cycles (as any change in the apparent T C of a refrigerant would have a negative impact on the performance of a device. 18 ) Splitting has been reported for samples with a completed diffusion process i.e.…”

Section: Introductionmentioning

confidence: 99%

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The dynamics of spontaneous hydrogen segregation in LaFe13−xSixHy

Baumfeld

Gercsi

Krautz

et al. 2014

Journal of Applied Physics

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By means of time-and temperature-dependent magnetization measurements, we demonstrate that the timescale of hydrogen diffusion in partially-hydrogenated LaFe 13−x Si x H y is of the order of hours, when the material is held at temperatures close to its as-prepared Curie temperature, T C0 . The diffusion constant is estimated to be D ≈ 10 −15 -10 −16 m 2 s −1 at room temperature. We examine the evolution of a magnetically phase-separated state upon annealing for 3 days at a range of temperatures around T C0 , and show that the thermodynamic driving force behind hydrogen diffusion and phase segregation may be attributed to the lower free energy of hydrogen interstitials in the ferromagnetic state relative to the paramagnetic state.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The dynamics of spontaneous hydrogen segregation in LaFe13−xSixHy

Baumfeld

Gercsi

Krautz

et al. 2014

Journal of Applied Physics

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Magnetoelectric Tuning of Pinning‐Type Permanent Magnets through Atomic‐Scale Engineering of Grain Boundaries

Yan

Schäfer

et al. 2020

Advanced Materials

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a diameter less than ≈100 nm. After that, a cleaning of the specimen at 5 kV was performed to remove the beam-damaged surface regions. The prepared tips were transferred into the load-lock chamber of APT, waited ≈2 h until the vacuum reached ≈10 −8 Pa (LEAP 3000 XHR), and then transferred into analysis chamber (≈10 −11 Pa) at 70 K. Data on Cameca LEAP 5000XR were also acquired, and only waited for half an hour before transferring the sample from APT load-lock to analysis chamber. The APT experiments were conducted using high-voltage mode with a pulse fraction of 15% at a base temperature of 70 K, a pulse frequency of 200 kHz, and an evaporation rate of 0.5. Atom probe data reconstruction and analysis were performed using CAMECA IVAS 3.8.4 software.

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Outstanding Comprehensive Performance of La(Fe, Si)₁₃H_y/In Composite with Durable Service Life for Magnetic Refrigeration

Wang

Zhang

Liu

et al. 2018

Adv Elect Materials

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temperature, has become a promisingly alternative technology to the existing vapor-compression refrigeration due to its energy efficiency and environment friendly. [4][5][6] As the core part of magnetic refrigeration, the comprehensive performance including MCE, thermal conductivity (λ), preparation and fabrication, corrosion resistance, and thermal and magnetic field cycling stabilities for magnetocaloric materials greatly affect the performance of the magnetic refrigerator. [7,8] Pure Gd, as the benchmark magnetic refrigerant, is commonly used in the active magnetic regenerator prototypes. [9,10] In particular, Gd metal could be produced into different shapes due to its good mechanical properties, such as thin plate, sphere, and microwire, and it has been demonstrated that microwire is more desirable for realizing a higher cooling performance. [11][12][13][14][15][16] However, Gd metal also has its disadvantages such as relatively low magnetic entropy change (ΔS M ), limited availability, and expensive price that hinder its large-scale commercialization. Therefore, a great number of magnetic materials with large MCE around room temperature have been extensively explored in the past decades. [2,6,[17][18][19][20] Unfortunately, although these new materials exhibit much better MCE than that of Gd, they still have severe shortcomings such as hard preparation Magnetic refrigeration based on magnetocaloric effect (MCE) has become a promisingly alternative technology to the conventional vapor-compression refrigeration. A great number of magnetic materials have been reported to exhibit larger MCE than that of the benchmark magnetic refrigerant Gd.However, these materials still have severe shortcomings on the "Non-MCE" properties, such as hard preparation and fabrication, low thermal conductivity λ, and poor corrosion resistance and cycling stabilities, which hinder the practical application of these materials. In this paper, a novel La(Fe, Si) 13 H y / In composite which is prepared by a readily available hot pressing method is demonstrated to exhibit an outstanding comprehensive performance with durable service life in various aspects. Noteworthily, the ΔS M does not decrease but increases with increasing nonmagnetic In metal. This advantageous anomaly is related to the strengthening of the first-order itinerant electron metamagnetic transition induced by residual compression stress and surrounded constraints in the composite. The present results make La(Fe, Si) 13 H y /In composite the most attractive alternative to Gd for magnetic refrigeration. Moreover, this work also provides a feasible way to solve the serious issues toward applications for La(Fe, Si) 13 -based materials and other brittle magnetocaloric materials.

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Reversible solid-state hydrogen-pump driven by magnetostructural transformation in the prototype system La(Fe,Si)13Hy

Cited by 48 publications

References 32 publications

The dynamics of spontaneous hydrogen segregation in LaFe13−xSixHy

The dynamics of spontaneous hydrogen segregation in LaFe13−xSixHy

Magnetoelectric Tuning of Pinning‐Type Permanent Magnets through Atomic‐Scale Engineering of Grain Boundaries

Outstanding Comprehensive Performance of La(Fe, Si)₁₃H_y/In Composite with Durable Service Life for Magnetic Refrigeration

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Reversible solid-state hydrogen-pump driven by magnetostructural transformation in the prototype system La(Fe,Si)13Hy

Cited by 48 publications

References 32 publications

The dynamics of spontaneous hydrogen segregation in LaFe13−xSixHy

The dynamics of spontaneous hydrogen segregation in LaFe13−xSixHy

Magnetoelectric Tuning of Pinning‐Type Permanent Magnets through Atomic‐Scale Engineering of Grain Boundaries

Outstanding Comprehensive Performance of La(Fe, Si)13Hy/In Composite with Durable Service Life for Magnetic Refrigeration

Contact Info

Product

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Outstanding Comprehensive Performance of La(Fe, Si)₁₃H_y/In Composite with Durable Service Life for Magnetic Refrigeration