Peaks in low field a.c. susceptibility of ferromagnetic Heusler alloys

The observation of a peak in the low field susceptibility need not always be taken to imply spin glass type of freezing. It may also be the consequence of a rapid build up of anisotropy field below the ordering temperature. The results of low field a.c. susceptibility measurements on Ru and Rh based ferromagnetic Heusler alloys presented here substantiate the above statement.