Physicists Induce 2D Ferromagnetism in Platinum

Physicists from the University of Groningen have induced magnetism in platinum by using an electric field generated with a paramagnetic ionic liquid. Since this affects only the surface of the platinum, a switchable 2D ferromagnet is created. The research was reported in the Science Advances journal on April 6, 2018.

This is Associate Professor Justin Ye, head of the Device Physics of Complex Materials group, which is part of the Zernike Institute for Advanced materials at the University of Groningen’s Faculty of Science and Engineering. (Image credit: Zernike Institute for Advanced Materials, University of Groningen)

Platinum is used, to a great extent, in electronics and jewelry. Despite the fact that platinum is an exceptional conductor and looks great, this precious metal lacks any magnetic characteristics. To date, this was the scenario: now, researchers from the University of Groningen have induced ferromagnetic states on the surface of a thin film of platinum. “You can tune magnets electrically by changing the number of carriers inside, which is one of the key ideas in spintronics. But so far, no one could generate magnets like that,” stated Associate Professor Justin Ye, chair of the Device Physics of Complex Materials group at the University of Groningen.

Ionic Liquid

Lei Liang, the first author of the study and a postdoc in Ye’s research team, designed a device through which ferromagnetism can be induced in non-magnetic platinum, employing a field effect produced by gating through an ionic medium known as an ionic liquid.

According to Ye, “The key here is that we used a paramagnetic ionic liquid, a new type of ionic liquid which we synthesized ourselves.”

Upon applying an electric field, the ions move toward the surface of the platinum, carrying magnetic and charge moments. Both moments have an impact on the surface layer of the platinum film, forming an atomically thin layer of magnetic platinum.

Spintronics

We were able to show that this is really a 2D magnet, and the magnetic state can extend to the room temperature,” stated Ye. “It is amazing that we could still add new properties to such a well-known material.”

In the recent past, several 2D magnets have been isolated from layered compounds; however, most of them are insulators and are magnetic only at very low temperatures. Producing them in a conductor can be beneficial in spintronics, a promising innovative kind of electronics, which is based on the magnetic moment, or spin, of electrons. The innovative finding indicates it is possible to switch the magnetism in a conductor on and off, which could enable the development of devices with the ability to control spin and charge at the same time.

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