Abstract
Magnetic properties and magnetocaloric effect of the ferrimagnetic compounds Gd4Co3 and (Gd0.9 Dy0.1)4Co3 have been studied. In Gd4 Co3, two successive magnetic-entropy changes occur due to a spin-reorientation transition at TSR =163 K and a ferrimagnetic-magnetic ordering transition at TC =220 K. For a field change from 0 to 5 T, -Δ SM max at TC is 5.74 J/kg K, the full width at half maximum (δ TFWHM) of the -Δ SM versus T curve has a high value of 131 K, and the refrigerant capacity is as high as 575 J/kg. TC can easily be tuned by Dy substitution for Gd and the magnetic-entropy change is increased simultaneously. -Δ SM max of (Gd0.9 Dy0.1)4Co3 at TC =145 K for the same field change has increased to 8.47 J/kg K. Our studies suggest that the successive magnetic transitions could enlarge the temperature interval, which makes this type of material meaningful for magnetic refrigeration in wider temperature regions than conventional materials.
| Original language | English |
|---|---|
| Article number | 053902 |
| Journal | Journal of Applied Physics |
| Volume | 105 |
| Issue number | 5 |
| DOIs | |
| State | Published - 2009 |
| Externally published | Yes |
Funding
This work was supported by the National Natural Science Foundation of China under Grant Nos. 30331030 and 50831006. FIG. 1. XRD patterns of Gd 4 Co 3 and ( Gd 0.9 Dy 0.1 ) 4 Co 3 . FIG. 2. Temperature dependences of the magnetizations of Gd 4 Co 3 (solid circles) and ( Gd 0.9 Dy 0.1 ) 4 Co 3 (solid triangles) at 0.01 T. The inset shows the first derivative of the magnetizations with respect to temperature. FIG. 3. (a) Field dependence of the magnetization of ( Gd 0.9 Dy 0.1 ) 4 Co 3 at 5 K. The inset shows the corresponding data for Gd 4 Co 3 . (b) Temperature dependence of the magnetization of ( Gd 0.9 Dy 0.1 ) 4 Co 3 at 1 T, measured with increasing field (open squares) and decreasing field (solid triangles). FIG. 4. Magnetic isotherms of ( Gd 0.9 Dy 0.1 ) 4 Co 3 in the temperature range of 98–184 K, measured with increasing field (open triangles) and decreasing field (solid squares) with temperature steps of 6 or 4 K. FIG. 5. Arrott plots of ( Gd 0.9 Dy 0.1 ) 4 Co 3 from 98 to 184 K. FIG. 6. Magnetic isotherms of Gd 4 Co 3 in the temperature interval of 108–264 K measured with increasing field (open triangles) and decreasing field (solid circles) with temperature steps of 6 K. FIG. 7. Temperature dependence of the magnetic-entropy change − Δ S M of Gd 4 Co 3 for magnetic-field changes Δ B = 0 – 2 T (solid circles), 0–5 T (solid triangles), and 0–7 T (solid squares). FIG. 8. Temperature dependence of the magnetic-entropy change − Δ S M of ( Gd 0.9 Dy 0.1 ) 4 Co 3 for magnetic-field changes Δ B of 0–2 T (solid circles), 0–5 T (solid triangles), and 0–7 T (solid squares).
| Funders | Funder number |
|---|---|
| National Natural Science Foundation of China | 50831006, 30331030 |