Using electricity to change magnetism

At TU Wien, researchers have taken a major step towards binding the electrical and magnetic properties of materials, which is crucial for possible applications in electronics.

It’s not exactly a new revelation that electricity and magnetism are closely related. And yet, magnetic and electrical effects have been studied separately for some time in the field of materials science. Magnetic fields will generally be used to influence the properties of magnetic materials, while electrical properties boil down to electrical voltage. Then we have the multiferroics – a special group of materials that combine the two. In a new development, TU Wien has successfully used electric fields to control the magnetic oscillations of certain ferrous materials. This has opened up huge potential for computer applications, as data is currently transferred as electrical signals but stored magnetically.

Electrical and magnetic materials: two-pole

In the field of solid state physics, it is often a question of working with properties of materials which can be influenced by magnetic or electric fields. As a rule, magnetic and electric effects can be studied separately because their causes are completely different. Magnetic effects occur because particles have an internal magnetic direction called “spin,” while electrical effects result from positive and negative charges in a material that can change position relative to each other.

“However, when it comes to materials with very specific spatial symmetries, the two can be combined,” says Prof. Andrei Pimenov from the Institute for Solid State Physics at TU Wien. He has been researching this particular type of material – “multiferroics” – for several years now. Multiferroics are currently considered a promising new field in solid-state physics on a global scale. Interesting experiments have already been done to research how magnetic and electric effects can be related and now Pimenov and his team of researchers have successfully used electric fields to control the high frequency magnetic oscillations of a material composed of iron, boron and rare earths. metals for the first time.

“The material contains iron atoms which are positively charged three times. They have a magnetic moment oscillating at a frequency of 300 GHz,” Pimenov explains. “There is no doubt that these oscillations could be controlled with the help of a magnetic field. But what we have been able to demonstrate is that these oscillations can be modified in a targeted way using a electric field.” This means that a dynamic magnetic effect – the state of magnetic oscillation of iron atoms – can be turned on or off using a static electric field.

Magnetic data storage, electrical writing

This development is particularly interesting for future electronics applications: “Our hard drives store data magnetically, but it’s incredibly difficult to write data quickly and accurately in the same way,” Pimenov explains. “It’s so much easier to apply an electric field with pinpoint precision, because all you need is a single pulse of voltage. The process is very fast and does not involve any significant energy loss. But now we could potentially have the ability to use materials that combine magnetic and electrical effects to combine the benefits of magnetic storage and electrical writing.