Synthesis, Structural, Magnetic, and Electrical Study of BaSrCo2O5, a Highly Disordered Cubic Perovskite

The influence of the partial substitution of Sr by Ba in the SrCoO3-y on its structure and properties has been investigated. SrBaCo2O5 is stable at room temperature as a cubic phase with a high oxygen vacancy concentration. This structure is stable up to 800 K. Above this temperature, the phase decomposes into a monodimensional rhombohedral (SrBa)(7)Co6O18 phase. At 1200 K, a reversible rhombohedral -> cubic transformation is observed, the rhombohedral phase remaining stable until room temperature. SrBaCo2O5 shows antiferromagnetic behavior with T-N approximate to 525 K. As determined by neutron diffraction data, the magnetic Co spins align ferromagnetically on the (111) planes and these planes are stacked antiferromagnetically in the normal direction (type II anti ferromagnet). The temperature dependence of the electrical conductivity indicates SrBaCo2O5 to be a semiconducting p-type material with an activation energy of similar to 0.3 eV.