ber hexagonale Perowskite mit Kationenfehlstellen. VII. Schwingungsspektroskopische Untersuchungen an rhomboedrischen 12 L-Stapelvarianten vom Typ Ba4BII(Re2 ? O12) and Ba4B2/3III ?1/3 (Re2 ? O12)

Crystal structures, magnetic properties, and DFT calculation of B-site defected 12L-perovskites Ba2La2MW2O12 (M = Mn, Co, Ni, Zn)

The synthesis, crystal structures and magnetic properties of Ba₂La₂MW₂O₁₂ (M  =  Mn, Co, Ni, Zn) were investigated. They crystallize in the 12-layer polytype of the perovskite structure with a regular cation defect in the B-site. The results of neutron diffraction measurements reveal that they adopt a rhombohedral structure with a space group R  -  3 and have a cation ordering between Ba and La ions in the A-site. In these compounds, the magnetic M ions form the 2D triangular lattice. From the results of magnetic measurements, the ferromagnetic ordering of M²⁺ ions for M  =  Co (T _C  =  1.3 K) and Ni (6.2 K) and the paramagnetic behavior (T  >  1.8 K) with an antiferromagnetic interaction for M  =  Mn are observed. From the DFT calculation, their band structures and magnetic interactions are discussed.