Materials for magnetic refrigeration between 2 K and 20 K

Barclay, J. A.; Steyert, W.A.

doi:10.1016/0011-2275(82)90098-4

Cited by 174 publications

(109 citation statements)

References 68 publications

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“…[13] Of these, gadolinium gallium garnet (GGG), which shows no long-range ordering down to 25 mK, has been established as a MCM for magnetic refrigeration in the liquid helium temperature regime. The absence of long-range ordering, high density of magnetic ions, chemical stability, and lack of single ion anisotropy (L = 0 for Gd 3+ ) allowing for the full magnetic entropy) to be extracted in high magnetic fields makes it an ideal MCM for T < 20 K. [14][15][16] In recent years, a number of Gd containing MCMs with better performance at 2 K have been reported [17][18][19][20] but GGG continues to be used and serves as the benchmark for MCMs in this temperature regime. However, for all the Gd-based magnetocalorics, the change in magnetic entropy is maximized in fields of 5 T or higher.…”

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confidence: 99%

“…) to be extracted in high magnetic fields makes it an ideal MCM for T < 20 K. [14][15][16] In recent years, a number of Gd containing MCMs with better performance at 2 K have been reported [17][18][19][20] but GGG continues to be used and serves as the benchmark for MCMs in this temperature regime. However, for all the Gd-based magnetocalorics, the change in magnetic entropy is maximized in fields of 5 T or higher.…”

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confidence: 99%

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Enhanced Magnetocaloric Effect from Cr Substitution in Ising Lanthanide Gallium Garnets Ln₃CrGa₄O₁₂ (Ln = Tb, Dy, Ho)

Mukherjee

Dutton

2017

Adv Funct Materials

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A detailed study on the crystal structure and bulk magnetic properties of Cr substituted Ising type lanthanide gallium garnets Ln 3 CrGa 4 O 12 (Ln = Tb, Dy, Ho) is carried out using room temperature powder X-ray and neutron diffraction, magnetic susceptibility, isothermal magnetization, and heat capacity measurements. The magnetocaloric effect (MCE) where the geometry of the magnetic lattice prevents all the nearest-neighbor magnetic interactions from being satisfied simultaneously. [8] This suppresses or in some cases, completely inhibits magnetic longrange ordering. Geometrically frustrated magnets (GFMs) typically show ordering features at T 0 ∼ θ CW /10 where θ CW is the Curie-Weiss temperature, thereby suppressing the ordering temperature. [9] In complex lanthanide oxides, the highly localized 4f orbitals have weak magnetic interactions, i.e., θ CW is small and so when the magnetic lattice is frustrated, ordering is suppressed to even lower T. The theoretical magnetic entropy that can be extracted is much higher than in transition metal compounds. GFMs with Ln 3+ ions are therefore ideal candidates for sub 20 K magnetocaloric materials (MCMs). Another advantage is that the lanthanides are chemically very similar but their magnetic properties vary widely. This allows tuning of the properties for optimization of the MCE. [10][11][12] The lanthanide gallium garnets, Ln 3 Ga 5 O 12, are a family of materials, where the magnetic Ln 3+ spins form two interpenetrating networks of ten membered-rings of corner-sharing triangles leading to a high degree of geometrical frustration. [13] Of these, gadolinium gallium garnet (GGG), which shows no long-range ordering down to 25 mK, has been established as a MCM for magnetic refrigeration in the liquid helium temperature regime. The absence of long-range ordering, high density of magnetic ions, chemical stability, and lack of single ion anisotropy (L = 0 for Gd 3+ ) allowing for the full magnetic entropy) to be extracted in high magnetic fields makes it an ideal MCM for T < 20 K. [14][15][16] In recent years, a number of Gd containing MCMs with better performance at 2 K have been reported [17][18][19][20] but GGG continues to be used and serves as the benchmark for MCMs in this temperature regime. However, for all the Gd-based magnetocalorics, the change in magnetic entropy is maximized in fields of 5 T or higher. Such high magnetic fields can only be produced using a superconducting magnet which again requires cooling using cryogens. For more practical applications, we need to focus on developing materials with high MCE in fields ≤ 2 T, attainable by a permanent magnet. This has been discussed in a recent study on Tb(HCO 2 ) 3 where the MCE is significantly higher than Gd(HCO 2 ) 3 at higher temperatures and lower fields as the Tb 3+ have Ising-like spins contrasted with the Heisenberg nature of the Gd 3+ spins. [21] For Ln 3 Ga 5 O 12 , the MCE in fields ≤2 T is expected to be maximized for the Ln 3+ having Ising-like spins, Magnetic Materials

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confidence: 99%

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confidence: 99%

Enhanced Magnetocaloric Effect from Cr Substitution in Ising Lanthanide Gallium Garnets Ln₃CrGa₄O₁₂ (Ln = Tb, Dy, Ho)

Mukherjee

Dutton

2017

Adv Funct Materials

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“…DOI: 10.1103/PhysRevLett.87.157203 PACS numbers: 75.30.Gw, 75.30.Sg, 75.50.Tt, 75.50.Xx It is well known that the magnetocaloric effect (MCE) has been useful in achieving very low temperatures (mK range) [1]. Up to now, most of MCE applications still remain in the low temperature range ͑,20 K͒ by using paramagnetic salts, e.g., Gd 3 Ga 3 O 12 [2]. For the MCE applications at high temperatures, different types of materials must be used [3][4][5][6].…”

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confidence: 99%

“…Up to now, most of MCE applications still remain in the low temperature range ͑,20 K͒ by using paramagnetic salts, e.g., Gd 3 Ga 3 O 12 [2]. For the MCE applications at high temperatures, different types of materials must be used [3][4][5][6].…”

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Anisotropic Magnetocaloric Effect in Nanostructured Magnetic Clusters

et al. 2001

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We report the first experimental observation of anisotropic magnetocaloric effect (MCE) in the Fe 8 clusters. It is found that the magnetic anisotropy plays a very important role in the determination of the magnetocaloric effect. The maximum and minimum MCE's are observed when the applied magnetic fields are parallel and perpendicular to the easy axis, respectively. The quantum spin Hamiltonian of a Fe 8 cluster is used to calculate the partition function and the magnetization in a range of temperature and magnetic field. Excellent quantitative agreement between the experimental data and calculation is observed. DOI: 10.1103/PhysRevLett.87.157203 PACS numbers: 75.30.Gw, 75.30.Sg, 75.50.Tt, 75.50.Xx It is well known that the magnetocaloric effect (MCE) has been useful in achieving very low temperatures (mK range) [1]. Up to now, most of MCE applications still remain in the low temperature range ͑,20 K͒ by using paramagnetic salts, e.g., Gd 3 Ga 3 O 12 [2]. For the MCE applications at high temperatures, different types of materials must be used [3][4][5][6]. The MCE in the superparamagnetic nanostructured materials has been recently studied by Shull and co-workers [7][8][9][10]. The results indicate that at higher temperatures the MCE is larger in the superparamagnetic nanostructures composites than in the pure paramagnetic materials. This makes the nanostructured composites appear to be very attractive candidates for the magnetic refrigeration in a very big temperature span. This enhancement was discussed by Shull et al. in considering a superparamagnetic system consisting of monosized and noninteracting magnetic clusters uniformly dispersed in a nonmagnetic media [7,10].It is well known that most magnetic nanoparticles or clusters exhibit a quite strong uniaxial magnetic anisotropy due to shape, stress, or surface effects [11], which governs the magnetic behavior of the particles [11,12]. Therefore, it is essential to understand the effect of the magnetic anisotropy in the MCE, particularly for the superparamagnetic materials. However, not much effort has been devoted to it. The reason could be that the materials used for magnetic refrigerants are either the ideal paramagnetic salts [2] or soft magnetic materials [3 -6] and therefore the effect of magnetic anisotropy is negligible. Theoretically, the anisotropic MCE was studied by using the Monte Carlo simulation for bulk ferromagnetic materials (or interacting magnetic clusters) with a uniaxial anisotropy in the vicinity of the Curie temperature [13]. Experimentally, a clean study of the anisotropic effect is generally hindered by the distribution of sizes and/or interactions. In this Letter, we report the anisotropy effect on the MCE in Fe 8 magnetic molecular crystals. With monosized clusters and well-defined anisotropic properties, this system offers, for the first time, a definite confirmation of the anisotropic MCE. It is shown that the magnetic anisotropy is important for both the qualitative and quantitative aspects of the MCE.The cluster Fe 8 with ...

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“…On the other hand, the materials with large MCE in low temperature regime are suitable for the gas liquifaction and could help cryogenic facility to reach milikelvin [10]. Up to now, some paramagnetic salts with the rareearth element such as Gd 3 Gd 5 O 12 , GdLiF 4 or GdF 3 have been commercially employed [11]. However, the MCE of most paramagnetic salts is relatively low, which restrains the application of paramagnetic salts.…”

Section: Introductionmentioning

confidence: 99%

Magnetocaloric properties in the PrFe2Ge2 antiferromgnet

Xu¹,

Gong²,

Lin³

et al. 2015

Proceedings of the 2015 International Conference on Structural, Mechanical and Material Engineering

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Materials for magnetic refrigeration between 2 K and 20 K

Cited by 174 publications

References 68 publications

Enhanced Magnetocaloric Effect from Cr Substitution in Ising Lanthanide Gallium Garnets Ln₃CrGa₄O₁₂ (Ln = Tb, Dy, Ho)

Enhanced Magnetocaloric Effect from Cr Substitution in Ising Lanthanide Gallium Garnets Ln₃CrGa₄O₁₂ (Ln = Tb, Dy, Ho)

Anisotropic Magnetocaloric Effect in Nanostructured Magnetic Clusters

Magnetocaloric properties in the PrFe2Ge2 antiferromgnet

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Materials for magnetic refrigeration between 2 K and 20 K

Cited by 174 publications

References 68 publications

Enhanced Magnetocaloric Effect from Cr Substitution in Ising Lanthanide Gallium Garnets Ln3CrGa4O12 (Ln = Tb, Dy, Ho)

Enhanced Magnetocaloric Effect from Cr Substitution in Ising Lanthanide Gallium Garnets Ln3CrGa4O12 (Ln = Tb, Dy, Ho)

Anisotropic Magnetocaloric Effect in Nanostructured Magnetic Clusters

Magnetocaloric properties in the PrFe2Ge2 antiferromgnet

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Enhanced Magnetocaloric Effect from Cr Substitution in Ising Lanthanide Gallium Garnets Ln₃CrGa₄O₁₂ (Ln = Tb, Dy, Ho)

Enhanced Magnetocaloric Effect from Cr Substitution in Ising Lanthanide Gallium Garnets Ln₃CrGa₄O₁₂ (Ln = Tb, Dy, Ho)