The magnetic and thermal properties of Gd3Al2 have been studied using four different experimental techniques. The magnetocaloric effect was measured directly in quasi-static fields up to 2 T and in pulsed fields up to 8 T, and calculated from the temperature and magnetic field dependencies of the heat capacity, and the magnetization. The compound orders ferrimagnetically at 281 K in zero magnetic field. In magnetic fields larger than ∼3 T a metamagnetic transition occurs between 40 and 50 K. The complex magnetic properties of Gd3Al2 also influence the behavior of the magnetocaloric effect. For a magnetic field change from 0 to 2 T the adiabatic temperature rise (ΔTad), which is a single maximum, is ∼2 K at the Curie temperature (TC=281 K). As the magnetic field increases from 2 to 5 T and greater, additional low temperature anomalies (two maxima and two minima) develop in the temperature range 15 to 150 K. Magnetocaloric effect maxima occur at 50 K (ΔTad= 3.4 K, ΔSmag = −8.8 J/kg K) and at 281 K (ΔTad = 7.7 K, ΔSmag = −7.2 J/kg K) for a magnetic field change from 0 to 10 T. Experimental data obtained from the different measurement techniques are in excellent agreement with each other.
Magnetocaloric Properties of Gd3Al2
Cryocoolers 10 ; Kapitel : 76 ; 639-645
2002-01-01
7 pages
Aufsatz/Kapitel (Buch)
Elektronische Ressource
Englisch
Magnetocaloric Properties of Gd~3Al~2
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