New magnetic material could revolutionise data storage

A new type of magnetic material has been discovered which could have wide-ranging applications within data storage and transmission.

Researchers at Trinity College Dublin have identified an alloy of manganese, ruthenium and gallium, or MRG. It has unusual properties that may allow it to revolutionise data storage, as well as increase wireless data transmission speeds significantly.

What is so remarkable about this magnet is that it is, outwardly, barely magnetic at all. MRG is a 'zero moment half metal' which has no net magnetic moment, but full spin polarisation. Having no magnetic moment means the material is free from its own demagnetising forces, as well as being immune to the influence of any external magnetic fields. This property, coupled with full spin polarisation, means the material should be extremely efficient when used in spintronics applications.

As reported in New Electronics, the 'big win' with MRG lies in its ability to shift the ferromagnetic resonance frequency – the maximum speed at which data is written or retrieved – into the low terahertz range. Magnets are employed in consumer electronics devices to read, store and transmit data. But a magnet that is resistant to magnetic fields could lead to limitless data storage, resulting in huge, superfast memory in personal computer devices. It could also eliminate the potential of external magnetic forces to ‘wipe’ computer data.

"The most difficult part was to understand that our new material was truly special," said lead researcher Dr Karsten Rode. "Once we realised there was a possibility that we could achieve full compensation of the magnetic moments, coupled with a large spin polarisation, we started checking to see if the 'zero moment half metal' hypothesis would stand intense scrutiny – and it did."

The team now wants to demonstrate spintronic functionality in a practical device. "This is challenging for a manganese-based alloy," according to Dr Rode. "The manganese is easily oxidised and this has to be avoided in a fully-functional thin-film device stack."