New Publication: Transition Metal Synthetic Ferrimagnets: Tunable Media for All-Optical Switching Driven by Nanoscale Spin Current

David Newman

Congratulations to fourth year PGRs David Newman and Connor Sait, who have co-authored the paper ‘Transition Metal Synthetic Ferrimagnets: Tunable Media for All-Optical Switching Driven by Nanoscale Spin Current‘, recently published in Nano Letters.

Synthetic ferrimagnets (SFi’s) represent a promising avenue for magnetic data storage devices since they have greater tunability (by varying the thickness of individual layers), simpler fabrication processes and better scalability than competing rare-earth based compounds. Here we use laser systems in Exeter and synchrotron X-ray techniques to identify an ultrafast spin current as the driving mechanism for switching magnetic states in our SFi sample before also exploring the effect of factors such as temperature on the observed switching behaviour. This work produces opportunities for further studies exploring the rich parameter space of SFi’s as well as advancing prospects for commercial usage in next generation data storage devices.

One of the paper’s authors, Connor Sait, says

Connor Sait

I’ve spent a lot of time training to become familiar with the laser techniques we use in the group so it’s great to see some of my early work recognised within the paper.

Please see below for full abstract:


All-optical switching of magnetization has great potential for use in future ultrafast and energy efficient nanoscale magnetic storage devices. So far, research has been almost exclusively focused on rare-earth based materials, which limits device tunability and scalability. Here, we show that a perpendicularly magnetized synthetic ferrimagnet composed of two distinct transition metal ferromagnetic layers, Ni3Pt and Co, can exhibit helicity independent magnetization switching. Switching occurs between two equivalent remanent states with antiparallel alignment of the Ni3Pt and Co magnetic moments and is observable over a broad temperature range. Time-resolved measurements indicate that the switching is driven by a spin-polarized current passing through the subnanometer Ir interlayer. The magnetic properties of this model system may be tuned continuously via subnanoscale changes in the constituent layer thicknesses as well as growth conditions, allowing the underlying mechanisms to be elucidated and paving the way to a new class of data storage devices.

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