Pr_0.5Sr_0.5-xBa_xMnO₃: Size and Mismatch Effects on Structural and Magnetic Transitions

Abstract

The structural and magnetic transitions in the Pr0.5Sr0.5-xBaxMnO3 series have been investigated by neutron diffraction and electron microscopy, in connection with the transport and magnetic properties, allowing a new phase diagram (T, x, or ) to be drawn. Two important points emerge from this study. First, a phase separation is observed for a large part of the diagram, described as a mixture of ferromagnetic, antiferromagnetic, and poorly ordered magnetic phases at low temperature for x > 0.2. Second, A-type antiferromagnetism (AFM) develops in nearly regular perovskite lattice. The case of Pr0.5Ba0.5MnO3 is also discussed because its microstructure is not conventional with local cationic ordering in the random A-site matrix.