The magneto-caloric effect of Gd5 Si2Ge2 compounds produced by various techniques is investigated in terms of their magnetization behaviors in the magnetic field from 0 to 2.0 T.The studied materials include arc-melte...The magneto-caloric effect of Gd5 Si2Ge2 compounds produced by various techniques is investigated in terms of their magnetization behaviors in the magnetic field from 0 to 2.0 T.The studied materials include arc-melted, annealed and sintered alloys.The results demonstrate that the Gd5Si2Ge2 alloys obtained under different processing conditions possess distinct magneto-caloric effect due to their various microstructures.Proper annealing treatment can enhance the magneto-caloric effect of the alloy remarkably.While the sintered alloy bears relatively lower value of magnetic entropy change ( △ SM) than arc-melted one.The magnetic entropy change of the annealed Gd5 Si2Ge2 alloy arrives the arrives the maximum value of - △SM = 15.29 J· kg-1· K-1 for magnetic field change under 2.0 T in the present work.展开更多
The magnetic phase transition and magneto- caloric effect of Gd5Si1.85Ge2.15 alloy are studied. The alloy was prepared from distilled commercial gadolinium. The major impurities (in wt.%) in the distilled commercial G...The magnetic phase transition and magneto- caloric effect of Gd5Si1.85Ge2.15 alloy are studied. The alloy was prepared from distilled commercial gadolinium. The major impurities (in wt.%) in the distilled commercial Gd are 0.016 O, 0.0054 C, and 0.0016 N. The impurities are higher than those in the high pure Gd but lower than those in commercial Gd. The results of X-ray diffraction and magnetic susceptibility show that there exists the first-order magnetic phase transition in the Gd5Si1.85Ge2.15 alloy at 253 K. The maximum of magnetic entropy change Smax is 12.5 J/kg·K near the temperature of magnetic phase transition in the alloy.展开更多
文摘The magneto-caloric effect of Gd5 Si2Ge2 compounds produced by various techniques is investigated in terms of their magnetization behaviors in the magnetic field from 0 to 2.0 T.The studied materials include arc-melted, annealed and sintered alloys.The results demonstrate that the Gd5Si2Ge2 alloys obtained under different processing conditions possess distinct magneto-caloric effect due to their various microstructures.Proper annealing treatment can enhance the magneto-caloric effect of the alloy remarkably.While the sintered alloy bears relatively lower value of magnetic entropy change ( △ SM) than arc-melted one.The magnetic entropy change of the annealed Gd5 Si2Ge2 alloy arrives the arrives the maximum value of - △SM = 15.29 J· kg-1· K-1 for magnetic field change under 2.0 T in the present work.
基金supported by the National Natural Science Foundation of China(Grant No.50071006)the“863”Program(Grant No.2002AA324101).
文摘The magnetic phase transition and magneto- caloric effect of Gd5Si1.85Ge2.15 alloy are studied. The alloy was prepared from distilled commercial gadolinium. The major impurities (in wt.%) in the distilled commercial Gd are 0.016 O, 0.0054 C, and 0.0016 N. The impurities are higher than those in the high pure Gd but lower than those in commercial Gd. The results of X-ray diffraction and magnetic susceptibility show that there exists the first-order magnetic phase transition in the Gd5Si1.85Ge2.15 alloy at 253 K. The maximum of magnetic entropy change Smax is 12.5 J/kg·K near the temperature of magnetic phase transition in the alloy.
