SPIN REORIENTATION IN THE NEW HEUSLER ALLOYS RU2MNSB AND RU2MNGE

Neutron diffraction studies have been made on the two compounds, Ru2Mn Sb and Ru(2)MuGe. The crystal structure of the Heusler L2(1) type is c onfirmed for both compounds. The magnetic order of these compounds is the same type 2 FCC antiferromagnetic structure. The magnetic moment o f Mn in Ru2MnGe is 3.8 mu(B) aligned along the [111] axis. In Ru2MnSb the Mn moment of 4.4 mu(B) is also aligned along the [111] axis above 100 K, but starts to deviate from [111] toward the [110] axis with dec reasing temperature. The Neel temperatures are 200 and 295 K for Ru2Mn Sb and Ru2MnGe, respectively.