Neutron diffraction study of the PrRu1−xFexSi and NdRu1−xFexSi solid solutions.: First example of canted ferromagnetic structure in the CeFeSi-type compounds

We report on powder neutron diffraction studies of both solid solutions PrRu1−xFexSi and NdRu1−xFexSi, which adopt the CeFeSi-type structure. All studied compounds order antiferromagnetically with a collinear antiferromagnetic structure which consists of ferromagnetic (0 0 1) R layers (with moments perpendicular to the layers, except for NdRu0.3Fe0.7Si with moment in the plane) antiferromagnetically coupled along the c-axis in the sequence + − − +. The NdRu0.3Fe0.7Si compound, which is characterized by spontaneous magnetization below 24 K, exhibits the first canted ferromagnetic structure (the ferromagnetic component is along the c-axis) characterized in the CeFeSi-type RTX compounds.