Exploiting Symmetry Mismatch to Control Magnetism in a Ferroelastic Heterostructure.

摘要: In the bulk, LaCoO_{3} (LCO) is a paramagnet, yet low-temperature ferromagnetism (FM) observed in tensile strained thin films, and its origin remains unresolved. Here, we quantitatively measured distribution of atomic density magnetization LCO films by polarized neutron reflectometry (PNR) found that layers near heterointerfaces exhibit reduced but an enhanced density, whereas film's interior (i.e., film bulk) shows opposite trend. We attribute nonuniformity to symmetry mismatch at interface, which induces structural distortion related ferroelasticity LCO. This assertion tested systematic application hydrostatic pressure during PNR experiments. The can be controlled rate -20.4% per GPa. These results provide unique insights into mechanisms driving FM while offering tantalizing observation tunable deformation CoO_{6} octahedra combination with ferroelastic order parameter.