Magnetocaloric properties of distilled gadolinium: Effects of structural inhomogeneity and hydrogen impurity

Journal Article · Mon Jun 16 00:00:00 EDT 2014 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4883744· OSTI ID:22299897

Burkhanov, G. S.; Kolchugina, N. B.; Chzhan, V. B.; Chistyakov, O. D. ^[1]; Tereshina, E. A. ^[2]; Tereshina, I. S. ^[1]; Politova, G. A. ^[1]; Badurski, D.; Drulis, H. ^[3]; Paukov, M.; Havela, L. ^[4]

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1. Baikov Institute of Metallurgy and Materials Science RAS, 119991 Moscow (Russian Federation)
2. Institute of Physics ASCR, 18221 Prague (Czech Republic)
3. Institute of Low Temperature and Structure Research PAS, 50-950 Wroclaw (Poland)
4. Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, 12116 Prague (Czech Republic)

High-purity Gd prepared by distillation is a structurally inhomogeneous system consisting of needle-shaped crystals of cross section 0.5–2.5 μm with near-c-axis orientation embedded in a matrix of nanosized (30–100 nm) grains. By measuring the magnetocaloric effect (MCE) directly, we find that the MCE values differ markedly for the plate-shaped samples cut out of a distillate along and perpendicular to the crystals. The effect of small controlled amounts of impurity (hydrogen) on the properties of distilled Gd is further studied. We observe opposite trends in the MCE response to hydrogen charging with respect to the crystal's orientation within the samples and discuss mechanisms interrelating the unique structural morphology with the impurity behavior. As an overall assessment, the Curie temperatures of α-GdH{sub x} solid solutions increase from 291 K up to 294 K when increasing hydrogen concentration x from 0 to 0.15. Hydrogenation is found to broaden the ferromagnetic-to-paramagnetic phase transition. Hydrogen-containing specimens demonstrate reversibility of MCE at these temperatures.

• OSTI ID: 22299897
• Journal Information: Applied Physics Letters, Vol. 104, Issue 24; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CHARGES
CROSS SECTIONS
CRYSTALS
CURIE POINT
DISTILLATION
GADOLINIUM
HYDROGEN ADDITIONS
HYDROGENATION
IMPURITIES
MAGNETIC PROPERTIES
NANOSTRUCTURES
PARAMAGNETISM
PHASE TRANSFORMATIONS
SOLID SOLUTIONS