Magnetic properties of an amorphous insulating spin glass: manganese aluminosilicate

The authors report on susceptibility and magnetisation measurements of amorphous manganese aluminosilicate and demonstrate that they can be considered as insulating spin glasses with large antiferromagnetic interactions. In particular, the cusp of chi (T) at T f is easily rounded under weak static magnetic fields. The in-field magnetisation curves for H<5 kOe and the field and time dependence of the remanent magnetisation have a similar behaviour to classical metallic spin glass alloys. The spin freezing temperature T f depends weakly on the frequency used in susceptibility measurements and this cannot be understood on the basis of the small magnetic particle model.