Scientists create magnetic nanohelics to control the rotation of electrons at room temperature

Researchers in South Korea have created magnetic nanohelics that can control the rotation of electrons at room temperature.

Spintronics, also called Spin Electronics, explores information processing using the intrinsic angular moment (spin) of electrons rather than only their electrical load. By pressing Spin, researchers aim to create data storage devices and logic that work faster and consume less energy. A major obstacle has been to create materials that can precisely and reliably define the direction of the rotation of the electrons.

In an important step for spin nanotechnology, researchers led by Professor Young Keun Kim of the University of Korea and Professor Ki Tae Nam of the National University of Seoul have created magnetic nanohelics that control the spin of electrons. The approach uses chiral magnetic materials to regulate rotation at room temperature, and the results were published in Science.

“These nanohelices are reaching a spin polarization beyond ~ 80% – just by their geometry and magnetism,” said Professor Keun Kim of the University of Korea, an author of co -corners of the study. He also pointed out: “This is a rare combination of structural chirality and intrinsic ferromagnetism, allowing a rotation filtering at room temperature without complex or cryogenic magnetic circuits, and provides a new way of engineering the behavior of electrons using structural design.”

Nanometric engineering chirality

The research team has successfully manufactured chiraux magnetic nanohelics on the left and right by controlling the process of metal crystallization electrochemically. A critical innovation involved the introduction of traces of chiral organic molecules, such as Cinchonine or Cinchonidine, which guided the formation of propellers with precisely defined return – a rarely achieved feat in inorganic systems.

In addition, the team has shown experimentally that when these nanohelics have a right -hander, they preferentially allow a direction of Spin pass, while the opposite rotation cannot. The above marks the discovery of a 3D inorganic helicoid nanostructure capable of controlling the rotation of the electrons.

“Chirality is well understood in organic molecules, where the transmission of a structure often determines its biological or chemical function,” noted Professor Ki Tae of the National University of Seoul, also the author of Co-Corresser. “But in inorganic metals and materials, the control of chirality during synthesis is extremely difficult, in particular on a nanometric scale. The fact that we can program the direction of the inorganic propellers simply by adding chiral molecules is a breakthrough in the chemistry of materials. »»

Measure and apply spin control

To confirm the chirality of nanohelics, the researchers have developed an evaluation method of chirality based on electromotive force (EMF) and measured the EMF generated by the propellers under the rotary magnetic fields. The left and right propellers have produced opposite EMF signals, allowing a quantitative verification of chirality even in materials that do not interact strongly with light.

The research team also noted that the magnetic material itself, thanks to its inherent magnetization (spin alignment), allows long distance spin transport at room temperature. This effect, maintained by strong exchange energy, is constant regardless of the angle between the chiral axis and the spin injection direction, and was not observed in the non -magnetic nanohelics of the same scale. The above marks the first measure of asymmetrical spin transport in a relatively macro chiral body. The team has also demonstrated a semiconductor system which showed conduction signals dependent on chirality, paving the way for practical spintronic applications.

Professor Kim highlighted the potential impact: “We believe that this system could become a platform for the spintronic chiral and the architecture of chiral magnetic nanostructures”. This work represents a powerful convergence of geometry, magnetism and spin transport, built from evolutionary inorganic materials. The ability to control the hand (left / right) and even the number of strands (double, multiple propellers) using this versatile electrochemical method should contribute significantly to the new areas of application.

Reference: The Sang Jeong, Eunjin Jong, Eunjin Won, Min Kyeo Lee, Min Moon, Min Moon, Min Moon, Min Moon, Minfan Moon, Min Week Lee, Jiong Kyok Lee, Sung Kyok Lee, September 4. Science.
Doi: 10.1126 / Science.ADX5963

Financing: National Korea Research Foundation

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