Tyndall National Institute
One of the consequences to our remarkable ease of access to the internet is that growth in creation of digital data is out-pacing growth of storage capacity. 3.5 zettabytes (3.5 trillion gigabytes) of new information was created in 2013. The International Data Corporation estimates that by 2020 demand for capacity will outstrip production by 6 zettabytes, or nearly double the demand of 2013 alone! Existing memory technologies are approaching their physical storage limitations as miniaturisation of electronic devices continues. Clearly, a new and disruptive memory technology is needed to bridge this evolving gap.
My research centres on the development, synthesis and investigation of new materials that possess both ferroelectric (permanent electric polarisation whose direction can be reversed by an applied electric field) and ferromagnetic (permanent magnetisation whose direction can be reversed by an applied magnetic field) properties. High data-density, energy-efficient memory devices based these so-called ‘multiferroic’ materials have been road-mapped as promising architectures for memory scaling beyond current technologies. One family of materials currently under investigation are those in the Bim+1Ti3Fem-3O3m+1 Aurivillius phase, system where on increasing the number of perovskite layers (m) in this naturally layered bismuth oxide system, the microstructural, magnetic and physical properties of the materials can be altered significantly.
Until very recently no materials showed genuine single-phase multiferroic effects at room temperature, therefore no such magnetoelectric multiferroic memory devices exist. My discovery (http://dx.doi.org/10.1111/jace.12467) of a rare and genuine multiferroic material (Aurivillius phase Bi6Ti2.8Fe1.52Mn0.68O18), demonstrating magnetoelectric coupling at room temperature could have significant implications for future generation computer storage applications, therefore my work focuses on exploiting this material and in addressing the intriguing research questions that this new discovery opens up.
Using my expertise in thin film deposition of complex multifunctional oxides, I fabricate high quality, uniform thin films using controlled synthetic methods, such as liquid injection chemical vapour deposition. This is necessary before reliable devices can be made. Understandings of how the magnetic and electronic polarisation components interact are being investigated at the nano-scale using advanced techniques, such as piezoresponse force microscopy under variable magnetic fields. Not only would an understanding of fundamental magnetoelectric mechanisms progress the development of this this rare single phase multiferroic material, it would also offer novel approaches to the design and development of new room temperature single-phase multiferroic materials.
The unique advantage of these advanced materials is that not only could they find application in high storage density, low-power memory devices that can be electrically written and magnetically read, a technology that takes advantage of simultaneous electric and magnetic memory states could allow for multiple bits per memory element. This would significantly advance data storage capabilities and sustain consumer demand for increasing levels of data creation.