Magnetocaloric effect in dysprosium

Journal Article · Thu Mar 01 04:00:00 EST 1979 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.327148· OSTI ID:6298920

Benford, S M

The magnetocaloric effect in polycrystalline Dy was measured between 84 and 280 K in measuring fields from 1 to 7 T. These adiabatic temperature changes reflect structural changes in Dy with applied field and temperature, and include the first magnetocaloric data for a helical antiferromagnet. These measurements were made to evaluate Dy as working material in magnetic refrigeration applications. Above T/sub N/ (179 K) a field increase always causes heating; below T/sub N/ fields less than about 2 T cause cooling for some values of initial temperature. The largest temperature increase with a 7 T field occurs at the Neel point (triangle-openT=11.5 K), and at fields below 2 T near the Curie point (triangle-openT=2 K at 100 K). For refrigeration purposes, the optimal working region for a Dy cooling element is field dependent. This Dy data suggests that, because of complex magnetic structure changes, antiferromagnetic rare earths may be useful for refrigeration over a broad temperature range near T/sub N/ at very high fields, and may be preferable to ferromagnetic materials over certain restricted temperature regions above the Curie point in low fields produced by permanent magnets (< or =1 T).

• Research Organization: NASA Lewis Research Center, Cleveland, Ohio
• OSTI ID: 6298920
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 50:B3; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals &amp; Alloys-- Structure &amp; Phase Studies
ANTIFERROMAGNETISM
COOLING
CRYSTALS
CURIE POINT
DYSPROSIUM
ELEMENTS
MAGNETISM
MAGNETO-THERMAL EFFECTS
METALS
NEEL TEMPERATURE
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
POLYCRYSTALS
RARE EARTHS
REFRIGERATION
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE