Al-Ge-Mn and Al-Cu-Ge-Mn Quasi-Crystals with Coercivity at Room Temperature : Condensed Matter

TLDR: In this article, Icosahedral quasi-crystals with coercivity at room temperature are found in rapidly solidified Al-Ge-Mn and Al-Cu-Ge -Mn alloys with compositions ranging form 20 to 25 at%Ge, 22.5 to 25%Mn, and 0 to 10%Cu.

Abstract: Icosahedral quasi-crystals with coercivity at room temperature are found in rapidly solidified Al-Ge-Mn and Al-Cu-Ge-Mn alloys with compositions ranging form 20 to 25 at%Ge, 22.5 to 25%Mn and 0 to 10%Cu. The highest Curie temperature is 533 K for Al52.5Ge22.5Mu25 and 467 K for Al40Cu10Ge25Mn25. The magnetization ( σ20) of the Al-Ge-Mn alloys in a field of 20 kOe at room temperature increases from 0.2 to 0.5 emu/g with increasing Ge and Mn contents and the coercivity (Hc) is in the range of 0.7 to 1.1 kOe. The replacement of Al by 10%Cu is found to bring about significant increases of σ20 and Hc to 3.9 emu/g and 1.8 kOe.