Nanoscale-Driven Crystal Growth of Hexaferrite Heterostructures for Magnetoelectric Tuning of Microwave Semiconductor Integrated Devices

Abstract

A nanoscale-driven crystal growth of magnetic hexaferrites was successfully demonstrated at low growth temperatures (25-40% lower than the temperatures required often for crystal growth). This outcome exhibits thermodynamic processes of crystal growth, allowing ease in fabrication of advanced multifunctional materials. Most importantly, the crystal growth technique is considered theoretically and experimentally to be universal and suitable for the growth of a wide range of diverse crystals. In the present experiment, the conical spin structure of Co2Y ferrite crystals was found to give rise to an intrinsic magnetoelectric effect. Our experiment reveals a remarkable increase in the conical phase transition temperature by ∼150 K for Co2Y ferrite, compared to 5-10 K of Zn2Y ferrites recently reported. The high quality Co2Y ferrite crystals, having low microwave loss and magnetoelectricity, were successfully grown on a wide bandgap semiconductor GaN. The demonstration of the nanostructure materials-based "system on a wafer" architecture is a critical milestone to next generation microwave integrated systems. It is also practical that future microwave integrated systems and their magnetic performances could be tuned by an electric field because of the magnetoelectricity of hexaferrites.

Synthesis of dense, fine‐grained hexagonal barium ferrite ceramics by two‐step sintering process

“…In recent years, hexagonal barium ferrite (BaFe 12 O 19 , BaM) has attracted much attention as potential materials for magnetic devices, such as permanent magnets and magnetic recording applications due to its high saturation magnetization and large uniaxial magnetocrystalline anisotropy field. It is well‐known that the magnetic properties of BaM ferrites are depended on its microstructure.…”