An integrated non-linear complex oxide thin film heterostructure with a tailored microstructure architecture design and a method of fabrication thereof, inclusive, is provided. The tailored microstructure architecture design mitigates the undesirable effects of thermal strain, hence provides strain relief, which enables the desirable simultaneously achievement of a high permittivity and high dielectric Q/low dielectric loss in concert with one another. The material design and fabrication method thereof; enables enhanced performance, low cost NLCO-based tunable devices which possess desirable attributes including, but are not limited to, tunable device miniaturization, wide tunability, minimization of signal attenuation, reduced device operational power and enhanced operational range. Furthermore, the materials and related process science protocols are complementary metal oxide semiconductor compatible, scalable and affordable.