Low-energy ‘melting’ of magnetism has potential for data storage

A new type of perovskite, the first-ever magnetic photoconductor, could lead the way to the next generation of data storage devices, according to its discoverers at the Ecole Polytechnique Federale de Lausanne in Switzerland.

A typical CH3NH3(Mn:Pb)I3 crystal developed in this study. Image: László Forró/EPFL
A typical CH3NH3(Mn:Pb)I3 crystal developed in this study. Image: László Forró/EPFL

The material is a modified form of perovskite, a mineral of great interest to developers of solar cells. A ferromagnetic photovoltaic material, its magnetic properties can be changed reversibly by heating. The EPFL researchers, led by post-doc Bálint Náfrádi, developed the organometallic substance, which contains manganese and lead, and in a paper in the journal Nature Communications they explain that it combines the properties of ferromagnetism, where structures that give rise to magnetism are aligned in a well-defined order, and photoconductivity, where shining light on the material generates free-moving electrons within its structure.

The combination of these two properties means that light frees electrons, which effectively “melt” magnetic structures inside the crystal. This can be achieved with a simple red LED, much weaker even than a laser pointer. The timescale for this transformation is a order of femtoseconds.

Although very much in the experimental state, these materials could, according to Náfrádi, be the basis for low-energy, high-capacity memory storage systems.

” These would combine the advantages of magnetic storage – long-term stability, high data density, nonvolatile operation and rewritability – with the speed of optical reading and writing,” he said.