Orientation dependent magnetocapacitance tuning in epitaxial (La,Sr) MnO3/(K,Na)NbO3-based heterostructures

We fabricated multiferroic heterostructures composed of La0.67Sr0.33MnO3 (LSMO) and (K0.48Na0.48Li0.04) (Nb0.81Ta0.15Sb0.04)O3 (KNN-LTS) on (0 0 1)-, (11 0)-, and (11 1)-oriented SrTiO3 substrates using pulsed laser deposition technique. X-ray diffraction confirmed the coherent growth of LSMO layers, while KNN-LTS layers exhibited partial relaxation in the heterostructures, with relaxation increasing from (001) to (111) orientations. Notably, the (11 1)-oriented LSMO, which displayed the highest out-of-plane lattice relaxation, exhibited su-perior magnetic properties. On the other hand, (00 1)-oriented sample showcased the maximum ferroelectric and piezoelectric properties due to its high elastic deformation, whereas (11 1)-oriented sample, characterized by higher intrinsic lattice deformation, demonstrated better dielectric properties. Our elemental analysis confirmed interface charge transfer, indicating the presence of magnetoelectric coupling within the heterostructures. Then, the magnetocapacitance effect was attributed to a combination of interface magnetoelectric coupling and magnetoresistance in LSMO. The (11 1)-oriented sample displayed a remarkable MC value of approximately 62% near the transition temperature (around 352 K) of LSMO, while the (11 0)-oriented sample reached the highest MC of approximately 65% at 300 K. These findings suggest that engineered ferroelectric/ferromagnetic heter-ostructures hold promise for high MC performance at room temperature and offer opportunities for modulation with crystallographic orientation, making them potentially valuable for applications in multiferroic devices.