MAGNETIC-PROPERTIES OF THE ICOSAHEDRAL (AL,GE)(70)PD12.5MN17.5 QUASI-CRYSTALS

A new series of icosahedral quasicrystals Al70-xGexPd12.5Mn17.5(0 less than or equal to x less than or equal to 15) was obtained by rapidly solidified melt-spinning method, and their magnetic properties were in vestigated. A pure single icosahedral phase was found at x less than o r equal to 6 and predominant icosahedral phase mixed with other second phases at 8 less than or equal to x less than or equal to 15. It was observed from the low- and high-field magnetic measurements that all t he compounds display a spin-glass behavior at low temperature T < T-F, and this is an intrinsic property of the quasicrystalline phase. The alloys with x greater than or equal to 10 exhibit unusual magnetic pro perties. At T > T-F these properties can be associated with crystallin e magnetic impurity AlGeMn, which is diluted in the paramagnetic quasi crystalline matrix in the form of fine particles or clusters. These cl usters can exhibit the properties of concentrated spin-glasses and/or superparamagnetic behavior.