Antiferromagnetic Order in Disorder-Induced Insulating Phase of SrRu1-xMnxO3 (0.4 ≤x ≤0.6)

We have performed powder neutron diffraction measurements on the solid solutions of SrRu 1- x Mn x O 3 , and found that the itinerant ferromagnetic order observed in pure SrRuO 3 changes into the C-type antiferromagnetic (AF) order with nearly localized d electrons in the intermediate Mn concentration range between x =0.4 and 0.6. With increasing x , the AF moment is strongly enhanced from 1.1 µ B ( x =0.4) to 2.6 µ B ( x =0.6), which is accompanied by the elongation of the tetragonal c / a ratio. These results suggest that the substitution of Mn for Ru suppresses the itinerant characteristic of the d electrons, and induces the superexchange interaction through the compression in the c plane. We have also found that the magnetic and transport properties observed in our tetragonal samples are similar to those of recently reported orthorhombic ones.