High field magnetocalorimetry below 1 K: specific heat of copper at 14 T

Leyarovski, E.; Leyarovska, L.; Popov, Chr.; Попов, О. Н.

doi:10.1016/0011-2275(88)90023-9

Cited by 9 publications

(2 citation statements)

References 41 publications

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“…Specific heat measurements between 1.8 and 10 K and 0−9 T were made using a Quantum Design Physical Properties Measurement System (QD PPMS) employing a time constant method at Florida State University. The platform was calibrated by use of a copper standard . The samples consisted of multiple crystals of Na 3 CrO 8 , eight crystals (aligned for the isotherm experiment) of K 2 NaCrO 8 , and single crystals of K 3 CrO 8 and Rb 3 CrO 8 .…”

Section: Methodsmentioning

confidence: 99%

Unhydrated Cr(V) Peroxychromates M₃CrO₈ (M = Na, K, Rb): Low-Dimensional Antiferromagnets Exhibiting Large Specific Heats at mK to 5 K Temperatures

Cage

Dalal

2001

Chem. Mater.

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The alkali-metal Cr(V) peroxychromates with the general formula M3CrO8 (M = Na, K, Rb, and combinations thereof) and the 3d1 ground state have been characterized by X-ray diffraction, variable frequency and variable temperature EPR, magnetic susceptibility, and thermodynamic techniques. K3CrO8 and Rb3CrO8 are isomorphous, with space groups as I4̄2m, whereas Na3CrO8 and K2NaCrO8 exhibit the orthorhombic space groups Cmc2 and Pbcm, respectively. Lattice parameters are presented for all of these compounds and are shown to depend sensitively on the cation. EPR measurements reveal that while the electronic ground state of Na3CrO8, K3CrO8, and Rb3CrO8 is 3d x 2 - y 2 , that of the mixed salts, such as K2NaCrO8 and Rb2NaCrO8, is 3d z 2 ; the origin of this switch is not yet clear. Specific heat measurements showed that K3CrO8 undergoes an antiferromagnetic ordering transition at T N = 0.38 K and displays a broad peak around 0.8 K, which can be interpreted in terms of a Bonner−Fisher model. Rb3CrO8 behaves similarly, with a broad peak at 0.52 K. Na3CrO8 exhibits a λ-like antiferromagnetic transition at 2.35 K, with K2NaCrO8 behaving similarly, with T N lower than 1.8 K. The exchange constants and the transition temperatures depend sensitively on the cation. These compounds all are found to exhibit large specific heats throughout the mK to 5 K temperature range, and the possibility exists of tuning the thermodynamic properties via dilution with compatible diamagnetic lattices such as M3NbO8. Their specific heat data indicate that they could find applications as tunable heat sinks and magnetic refrigerants in the mK to 5 K range.

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Section: Methodsmentioning

confidence: 99%

Unhydrated Cr(V) Peroxychromates M₃CrO₈ (M = Na, K, Rb): Low-Dimensional Antiferromagnets Exhibiting Large Specific Heats at mK to 5 K Temperatures

Cage

Dalal

2001

Chem. Mater.

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“…Heat capacity was measured between 1.8 and 10 K on single-crystal samples (∼2−3 mg) using a Quantum Design Physical Properties Measurement System (QD PPMS) employing a time constant method. The platform was calibrated using a copper standard …”

Section: Methodsmentioning

confidence: 99%

Hydrated Cr(V) Peroxychromates M₃CrO₈·XH₂O (M = Li, Na, Cs): Model 3d¹Systems Exhibiting Linear Chain Behavior and Antiferromagnetic Interactions

et al. 2001

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A new class of Cr(V) peroxychromates, those containing waters of hydration (Li3CrO8·10H2O, Na3CrO8·14H2O and Cs3CrO8·3H2O), has been synthesized and characterized by single-crystal X-ray diffraction, magnetic susceptibility, specific heat, and EPR techniques. The Li salt crystallizes into the orthorhombic (Cmcm) group, whereas the Na and Cs salts exhibit the triclinic (P1̄) and monoclinic P2(1)/n space groups, respectively. Crystal structure analysis indicated the availability of low-dimensional spin-exchange pathways. The orientation dependence of the EPR line width exhibited the (3 cos2 θ − 1)4/3 behavior characteristic of linear chain compounds, with θ = 0 coinciding with the chain axis. Correlation of the EPR and X-ray data allowed for the explicit determination of the magnetic chain axes in the crystal and molecular frameworks. Magnetic susceptibility, χ, measurements on oriented single crystals yielded negative values for the Curie−Weiss temperatures, indicating dominant antiferromagnetic interactions. The χ data yielded the Curie constants that appear to be inversely related to the number of waters of hydration in the crystal structure; this observation is not yet understood. Correlation of the EPR line width, nearest neighbor distances, and Curie constants attested to the essential correctness of the linear chain spin exchange and dipolar fields in the Li and Cs salts, and to a lesser extent also for the Na salt. The specific heat data indicated that all these compounds have the potential to be useful for devices requiring strong heat sinks as well as magnetic refrigerants in the 250 mK temperature regime. They appear to be good as model systems for theoretical investigations on low-dimensional magnetic lattices and for understanding aspects of Cr(VI)-based catalysis and carcinogenesis.

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Theoretical study of lattice heat capacity, thermal expansion and phonon-limited resistivity of transition metals

Milman

Grishchenko

Evlashina

et al. 1992

Journal of Physics and Chemistry of Solids

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High field magnetocalorimetry below 1 K: specific heat of copper at 14 T

Cited by 9 publications

References 41 publications

Unhydrated Cr(V) Peroxychromates M₃CrO₈ (M = Na, K, Rb): Low-Dimensional Antiferromagnets Exhibiting Large Specific Heats at mK to 5 K Temperatures

Unhydrated Cr(V) Peroxychromates M₃CrO₈ (M = Na, K, Rb): Low-Dimensional Antiferromagnets Exhibiting Large Specific Heats at mK to 5 K Temperatures

Hydrated Cr(V) Peroxychromates M₃CrO₈·XH₂O (M = Li, Na, Cs): Model 3d¹Systems Exhibiting Linear Chain Behavior and Antiferromagnetic Interactions

Theoretical study of lattice heat capacity, thermal expansion and phonon-limited resistivity of transition metals

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High field magnetocalorimetry below 1 K: specific heat of copper at 14 T

Cited by 9 publications

References 41 publications

Unhydrated Cr(V) Peroxychromates M3CrO8 (M = Na, K, Rb): Low-Dimensional Antiferromagnets Exhibiting Large Specific Heats at mK to 5 K Temperatures

Unhydrated Cr(V) Peroxychromates M3CrO8 (M = Na, K, Rb): Low-Dimensional Antiferromagnets Exhibiting Large Specific Heats at mK to 5 K Temperatures

Hydrated Cr(V) Peroxychromates M3CrO8·XH2O (M = Li, Na, Cs): Model 3d1Systems Exhibiting Linear Chain Behavior and Antiferromagnetic Interactions

Theoretical study of lattice heat capacity, thermal expansion and phonon-limited resistivity of transition metals

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Unhydrated Cr(V) Peroxychromates M₃CrO₈ (M = Na, K, Rb): Low-Dimensional Antiferromagnets Exhibiting Large Specific Heats at mK to 5 K Temperatures

Unhydrated Cr(V) Peroxychromates M₃CrO₈ (M = Na, K, Rb): Low-Dimensional Antiferromagnets Exhibiting Large Specific Heats at mK to 5 K Temperatures

Hydrated Cr(V) Peroxychromates M₃CrO₈·XH₂O (M = Li, Na, Cs): Model 3d¹Systems Exhibiting Linear Chain Behavior and Antiferromagnetic Interactions