Enhanced Structural and Magnetic Coupling in a Mesocrystal-Assisted Nanocomposite

Benefiting from the advances made in well-controlled materials synthesis techniques, nanocomposites have drawn considerable attention due to their enthralling physics and functionalities. In this work, we report a new heteroepitaxial mesocrystal-perovskite nanocomposite, (NiFe₂O₄)_0.33:(La_0.67Ca_0.33MnO₃)_0.67. Elaborate structural studies revealed that tiny NiFe₂O₄ nanocrystals aggregate into ordered octahedral mesocrystal arrays with {111} facets together with a concomitant structural phase transition of the La_0.67Ca_0.33MnO₃ matrix upon postannealing process. Combined magnetic and X-ray absorption spectroscopic measurements show significant enhancement in the magnetic properties at room temperature due to the structural evolution of magnetic NiFe₂O₄ and the consequent magnetic coupling at the heterointerfaces mediating via well connected octahedrons of Mn-O₆ in La_0.67Ca_0.33MnO₃ and (Ni,Fe)-O₆ in NiFe₂O₄. This work demonstrates an approach to manipulate the exciting physical properties of material systems by integrating desired functionalities of the constituents via synthesis of a self-assembled mesocrystal embedded nanocomposite system.