Effects of large cation size-disorder on the magnetic properties of the rare earth cobaltates, Ln0.5Ba0.5CoO3

Magnetic and electrical properties of Ln0.5Ba0.5CoO3−δ with Ln=Dy and Er have been investigated to examine the effects of large cation size-disorder. While the Dy compound shows the small magnetic anomaly around 290 K just as the Gd derivative, the Er compound is essentially paramagnetic due to the large cation size-disorder. Compositions with the same average A-site cation radii as Dy0.5Ba0.5CoO2.91 and Er0.5Ba0.5CoO2.9, but with smaller size-disorder, show progressive evolution of ferromagnetism and metallic properties with decreasing disorder.