Interrelation between Structure – Magnetic Properties in La_0.5Sr_0.5CoO₃

Abstract

scale and tailored to have desired properties. Modern synthesis techniques, for instance, can exploit this deeper understanding of structure -property relationships and fabricate epitaxial superlattices composed of alternating layers, each with their own functional property and the complete stack operating as a highly complex and self-contained device. [ 4,5 ] The ideal perovskite structure has cubic symmetry characterized by BO 6 octahedra with equal B-O bond angles/distances in all directions. However, differences in the ionic radii of the A and B atoms lead to tilts and rotations of the octahedra and lowering of structural symmetry. Glazer [ 6 ] devised a notation to describe these tilts along the three principle crystallographic directions and tabulated the families of half-order peaks associated with various lowered structural symmetries. In epitaxial fi lms, the lattice mismatch between the fi lm and the substrate results in differing in-plane vs. out-of-plane bond angles/distances; and/or to a change in the pattern of BO 6 tilts/rotations. These structural distortions occur commonly in perovskites and while several theoretical studies have highlighted their impact on the functional properties, [7][8][9][10]

Towards 3D Mapping of BO6 Octahedron Rotations at Perovskite Heterointerfaces, Unit Cell by Unit Cell

“…13À16 Examples of experimental studies include BO 6 rotation controlled polar order in BiFeO 3 , 17 increased Curie temperature in La 0.7 Sr 0.3 MnO 3 (LSMO)/Eu 0.7 Sr 0.3 MnO 3 (ESMO) superlattices, 18 altered magnetization and electrical conductivity in LSMO thin films, 19 and modified magnetic properties in La 0.5 Sr 0.5 CoO 3 . 20 Notably, BO 6 rotation engineering has recently been applied to generate room temperature electric polar and weak ferromagnetic behavior in the layered perovskite (Ca y Sr 1Ày ) 1 further demonstrating the significance of this strategy. 21 To fully understand the heterostructures created using this new route, we need to identify the BO 6 rotations, ideally both the symmetry and the magnitude, as a function of the distance from the heterointerface.…”

Engineered superlattices with crossover from decoupled to synthetic ferromagnetic behavior

“…In LSMO thin films, deviations from the bulk a − a − a − BO 6 tilt patterns only persisted for a few unit cells away from the substrate interface [19,20]. In contrast, for La 0.5 Sr 0.5 CoO 3 thin films, the BO 6 tilt patterns observed by synchrotron x-ray diffraction (XRD) differed from that of bulk La 0.5 Sr 0.5 CoO 3 and that of the underlying substrate (NdGaO 3 and La 0.3 Sr 0.7 Al 0.65 Ta 0.35 O 3 (LSAT)), and this modified tilt pattern extended throughout the full 100 Å film thickness [21].…”

Structural “ δ Doping” to Control Local Magnetization in Isovalent Oxide Heterostructures

“…Through the design and control of these interfacial perturbations to atomic structure, substantial changes to electronic and magnetic properties have been induced in ultrathin epitaxial films at the film/substrate interface [16][17][18][19]. Interfacial coupling is also operative in superlattices, where the presence of multiple interfaces, a wide array of combinations of constituent materials, and the ability to tune the interfacial distance with respect to the coupling length scale enables new possibilities for structure-based design and control over functional properties [20][21][22][23][24].…”