Correlations of structure and magnetism in perovskite oxide thin films

Description: Perovskite oxides (ABO3) form one of the most intriguing class of transition metal oxides exhibiting fascinating properties such as, high temperature superconductivity, colossal magnetoresistance, magnetoelectric effect, multiferroicity etc. The greatest advantage of this class of oxides lies in their ability to accommodate almost any element of the periodic table and high compatibility when combined with other oxides of the same or other families. The corner connected octahedra BO6 plays the key role in controlling the functional behavior of the perovskite oxides. Any variation in B-O-B bond-length and bond-angle alters the shape, size and connectivity of octahedra within material resulting in the wide-ranging physical and chemical properties of these oxides. The structure-property correlation in these oxides offers many routes to modulate the functional properties of these materials. The bulk properties can be altered by chemical substitution or hydrostatic pressure. However, mismatch strain can give rise to interesting or unexpected behaviors in thin films or multilayer structures. 
BaFeO3-δ (BFO) exists in a variety of structural and magnetic phases depending on oxygen stoichiometry. Being room-temperature ferromagnetic insulator, BFO has long been studied as a potential candidate for magnetoelectric materials. In the major part of this talk I will discuss the influence doping, oxygen annealing and epitaxial strain on the structural and magnetic properties of BFO thin films.  
Ce-doped Pr0.5Ca0.5MnO3 (PCMO) constitutes a material with varied structural and magnetic properties depending on the content of Ce at the Pr-site. It is found to show meta magnetism along with structural transformations in bulk form. I will briefly discuss how this particular system would behave in thin film form with varying epitaxial strain.