| Popis: |
In this work we calculate the magnetic properties and the magnetocaloric effect in Gd1−yDyyAl2 (y = 0, 0.25, 0.5, 0.75 and 1). The model Hamiltonian includes contributions from the Zeeman effect, the crystalline electrical field anisotropy and the exchange interactions among Gd–Gd, Gd–Dy and Dy–Dy ions. To obtain a composite with ΔST as constant as possible in the temperature range from T = 60 K to 170 K, the appropriate concentrations of the five compounds investigated were calculated using the Smaili and Chahine method. The magnetization and ΔST dependences on temperature in the composite were simulated and compared with the partial contributions of the single magnetic component materials. Also, the magnetic field dependence on magnetization was investigated in Gd0.25Dy0.75Al2, where the discontinuous spin reorientation transitions were predicted for magnetic fields lower than 2 T, applied along direction. |
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