Single crystals of the perovskite developed in this study; on the right a diagram showing the melting of the ferromagnetic state © M. Spina, E. Horváth/EPFL
EPFL scientists have developed a new perovskite material with unique properties to build next-gen hard drives. As we generate more and more data, we need storage systems, e.g. hard drives, with higher density and efficiency. But this also requires materials whose magnetic properties can be quickly and easily manipulated in order to write and access data on them. EPFL scientists have now developed a perovskite material whose magnetic order can be rapidly changed without disrupting it due to heating.
The lab of Laszló Forró synthesized a ferromagnetic photovoltaic material. Perovskite photovoltaics are gradually becoming a cheaper alternative to current silicon systems. But this material, which is a modified version of perovskite, exhibits some unique properties that make it particularly interesting as a material to build next-generation digital storage systems.
“We have essentially discovered the first magnetic photoconductor,” says Bálint Náfrádi. This new crystal structure combines advantages of both ferromagnets, whose magnetic moments are aligned in a well-defined order, and photoconductors, where light illumination generates high density free conduction electrons. The combination of the 2 properties produced an entirely new phenomenon: the “melting” of magnetization by photo-electrons ie electrons emitted from a material when light hits it.
In the new perovskite material, a simple red LED—much weaker than a laser pointer—is enough to disrupt, or “melt” the material’s magnetic order and generate a high density of travelling electrons, which can be freely and continuously tuned by changing the light’s intensity. The timescale for shifting the magnetic in this material is also very fast, virtually needing only quadrillionths of a second.
Though still experimental, these properties mean the new material can be used to build the next generation of memory-storage systems, with higher capacities with low energy demands. “This study provides the basis for the development of a new generation of magneto-optical data storage devices,” says Náfrádi. “These would combine the advantages of magnetic storage—long-term stability, high data density, non-volatile operation and re-writability— with the speed of optical writing and reading.”
http://actu.epfl.ch/news/a-new-perovskite-could-lead-the-next-generation-of/
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