Spectacular switching from ferrimagnetism to antiferromagnetism by zinc doping in "114" orthorhombic CaBaCo4O7

We report a spectacular switching from ferrimagnetism to antiferromagnetism in orthorhombic "114" CaBaCo4O7 by doping with a diamagnetic cation, Zn2+. Magnetic hysteresis loops, together with M(T) and chi'(T) curves at various frequencies, show that ferrimagnetism is abruptly converted to antiferromagnetism below T similar to 80 K for less than 3% Zn doping, with the simultaneous appearance of local magnetic frustration. A model is proposed based on the ordered doping of Zn2+ at Co2+ sites in the ferromagnetic zig-zag chains of CaBaCo4O7, leading, by domino effect, to ferrimagnetic domains distributed at random and ordered at 180 degrees. The boundaries of the junction of these domains contain Zn2+ and are magnetically frustrated. The crucial role of such ferromagnetic zig-zag chains for designing and tuning magnetic properties in oxides with a triangular metallic lattice is emphasized. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4725517]