New magnetic materials seek memory, wireless applications

February 04, 2015 // By Graham Prophet
A class of structures called hybrid multiferroics may yeild improved data storage and new wireless applications.

To exploit and control magnetism, technology often relies on electromagnets, which limit hardware configurations due to their size and energy consumption. As an alternative, scientists are beginning to develop hybrid nanomaterials that are responsive to both electric and magnetic fields. These materials can save energy and space, and may open up new applications.

Creating materials that can be influenced by both magnetic and electric forces – so called ‘multiferroics’ – is an emerging field that is currently being addressed mainly by academics, although there is interest from companies with interests in data storage, magnetic sensors and microwave components. Power savings are one incentive, but another factor is the multi-functionality they could offer, possibly leading to new forms of information storage.

“Some materials exhibit spontaneous electric or magnetic order. These materials are called ferroelectric and ferromagnetic, respectively,” explains Professor Sebastiaan van Dijken, leader of the Nanomagnetism and Spintronics Group at Aalto University, Espoo, Finland. “However, among these two ferroic materials there is little overlap. While it is possible to create materials that achieve this overlap in a laboratory setting, it is usually at very low temperatures and so is fairly useless in terms of the development of components for nanoelectronic devices.”

Prof. Van Dijken’s group received a €1.5million European Union grant in 2012, to fund a five-year project. To further its investigations, the group has developed a microscopy technique that employs an ultra-fast camera, to enable the imaging of ferroelectric-ferromagnetic coupling effects in an applied electric field with nanosecond-precision. Study objectives include finding out if, and how, it is possible to manipulate the magnetic properties of materials by electrical means in nanoscale structures and in the time frame of nanoseconds.

Professor van Dijken’s team have been creating hybrid structures using one stable ferroelectric material and one stable ferromagnetic material. Built at the nanoscale, thin films of each material are linked together by strong coupling at their interfaces, enabling them to be