FeMiT · Ferrites-by-design for Millimeter-wave and Terahertz Technologies

Robust disruptive materials will be essential for the “wireless everywhere” to become a reality. This is because we need a paradigm shift in mobile communications to meet the challenges of such an ambitious evolution. In particular, some of these emerging technologies will trigger the replacement of the magnetic microwave ferrites in use today. This will namely occur with the forecasted shift to high frequency mm-wave and THz bands and in novel antennas that can simultaneously transmit and receive data on the same frequency. In both cases, operating with state-of-the-art ferrites would require large external magnetic fields incompatible with future needs of smaller, power-efficient devices. To overcome these issues, we target ferrites featuring the so far unmet combinations of low magnetic loss and large values of magnetocrystalline anisotropy, magnetostriction or magnetoelectric coupling. The objective of FeMiT is developing a novel family of orthorhombic ferrites based on ε-Fe2O3, a room-temperature multiferroic with large magnetocrystalline anisotropy. Those properties and unique structural features make it an excellent platform to develop the sought-after functional materials for future compact and energy-efficient wireless devices. In the first part of FeMiT we will explore the limits and diversity of this new family by exploiting rational chemical substitutions, high pressures and strain engineering. Soft chemistry and physical deposition methods will be both considered at this stage.The second part of FeMiT entails a characterization of functional properties and selection of the best candidates to be integrated in composite and epitaxial films suitable for application. The expected outcomes will provide proof-of-concept self-biased or voltage-controlled signal-processing devices with low losses in the mm-wave to THz bands, with high potential impact in the development of future wireless technologies.