Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International



Home > Press > Spintronics just got faster

This 2-dimensional ultrafast UV spectroscopy set-up at EPFL's laboratory of ultrafast spectroscopy, used to carry out the measurements in this study.

Alain Herzog/EPFL
This 2-dimensional ultrafast UV spectroscopy set-up at EPFL's laboratory of ultrafast spectroscopy, used to carry out the measurements in this study.

Alain Herzog/EPFL

Abstract:
In a tremendous boost for spintronic technologies, EPFL scientists have shown that electrons can jump through spins much faster than previously thought.

Spintronics just got faster

Lausanne, Switzerland | Posted on July 20th, 2015

Electrons spin around atoms, but also spin around themselves, and can cross over from one spin state to another. A property which can be exploited for next-generation hard drives. However, "spin cross-over" has been considered too slow to be efficient. Using ultrafast measurements, EPFL scientists have now shown for the first time that electrons can cross spins at least 100,000 times faster than previously thought. Aside for its enormous implications for fundamental physics, the finding can also propel the field of spintronics forward. The study is published in Nature Chemistry.

The rules of spin

Although difficult to describe in everyday terms, electron spin can be loosely compared to the rotation of a planet or a spinning top around its axis. Electrons can spin in different manners referred to as "spin states" and designated by the numbers 0, 1/2, 1, 3/2, 2 etc. During chemical reactions, electrons can cross from one spin state to another, e.g. from 0 to 1 or 1/2 to 3/2.

Spin cross-over is already used in many technologies, e.g. optical light-emitting devices (OLED), energy conversion systems, and cancer phototherapy. Most prominently, spin cross-over is the basis of the fledgling field of spintronics. The problem is that spin cross-over has been thought to be too slow to be efficient enough in circuits.

Spin cross-over is extremely fast

The lab of Majed Chergui at EPFL has now demonstrated that spin cross-over is considerably faster than previously thought. Using the highest time-resolution technology in the world, the lab was able to "see" electrons crossing through four spin states within 50 quadrillionths of a second - or 50 femtoseconds.

"Time resolution has always been a limitation," says Chergui. "Over the years, labs have used techniques that could only measure spin changes to a billionth to a millionth of a second. So they thought that spin cross-over happened in this timeframe."

Chergui's lab focused on materials that show much promise in spintronics applications. In these materials, electrons jump through four spin-states: from 0 to 1 to 2. In 2009, Chergui's lab pushed the boundaries of time resolution to show that this 0-2 "jump" can happen within 150 femtoseconds - suggesting that it was a direct event. Despite this, the community still maintained that such spin cross-overs go through intermediate steps.

But Chergui had his doubts. Working with his postdoc Gerald Auböck, they used the lab's world-recognized expertise in ultrafast spectroscopy to "crank up" the time resolution. Briefly, a laser shines on the material sample under investigation, causing its electrons to move. Another laser measures their spin changes over time in the ultraviolet light range.

The finding essentially demolishes the notion of intermediate steps between spin jumps, as it does not allow enough time for them: only 50 quadrillionths of a second to go from the "0" to the "2" spin state. This is the first study to ever push time resolution to this limit in the ultraviolet domain. "This probably means that it's even faster," says Chergui. "But, more importantly, that it is a direct process."

From observation to explanation

With profound implications for both technology and fundamental physics and chemistry, the study is an observation without an explanation. Chergui believes that the key is electrons shuttling back-and-forth between the iron atom at the center of the material's molecules and its surrounding elements. "When the laser light shines on the atom, it changes the electron's spin angle, affecting the entire spin dynamics in the molecule."

It is now up to theoreticians to develop a new model for ultrafast spin changes. On the experimental side of things, Chergui's lab is now focusing on actually observing electrons shuttling inside the molecules. This will require even more sophisticated approaches, such as core-level spectroscopy. Nonetheless, the study challenges ideas about spin cross-over, and might offer long-awaited solutions to the limitations of spintronics.

###

This work was supported by the Swiss National Science Foundation via the National Centre of Competence in Research Molecular Ultrafast Science and Technology, and by a Research Equipment grant.

Reference

Auböck G, Chergui M. Sub-50 fs photo-induced spin cross-over in [Fe(bpy)3]2+. Nature Chemistry 20 July 2015. DOI: 10.1038/nchem.2305

####

For more information, please click here

Contacts:
Nik Papageorgiou

41-216-932-105

Copyright © Ecole Polytechnique Fédérale de Lausanne

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

Physics

Pitt researchers create nanoscale slalom course for electrons: Professors from the Department of Physics and Astronomy have created a serpentine path for electrons November 27th, 2020

A new candidate material for quantum spin liquids November 12th, 2020

News and information

Phytoplankton disturbed by nanoparticles: Due to its antibacterial properties, nanosilver is used in a wide range of products from textiles to cosmetics; but nanosilver if present at high concentrations also disrupts the metabolism of algae that are essential for the aquatic food November 27th, 2020

Quantum nanodiamonds may help detect disease earlier: The quantum sensing abilities of nanodiamonds can be used to improve the sensitivity of paper-based diagnostic tests, potentially allowing for earlier detection of diseases such as HIV, according to a study led by UCL research November 27th, 2020

One-way street for electrons: Scientists observe directed energy transport between neighbouring molecules in a nanomaterial November 27th, 2020

New insights into memristive devices by combining incipient ferroelectrics and graphene November 27th, 2020

Chemistry

Light-controlled nanomachine controls catalysis: A molecular motor enables the speed of chemical processes to be controlled using light impulses November 23rd, 2020

Smaller than Ever—Exploring the Unusual Properties of Quantum-sized Materials November 13th, 2020

Industrial-strength brine, meet your kryptonite: Boron nitride coating is key ingredient in hypersaline desalination technology November 6th, 2020

Display technology/LEDs/SS Lighting/OLEDs

Improving quantum dot interactions, one layer at a time: Scientists have found a way to control an interaction between quantum dots that could lead to more efficient solar cells November 20th, 2020

Spintronics

Spintronics advances -- Controlling magnetization direction of magnetite at room temperature: Scientists develop an energy-efficient strategy to reversibly change 'spin orientation' or magnetization direction in magnetite at room temperature November 20th, 2020

A new candidate material for quantum spin liquids November 12th, 2020

A four-state magnetic tunnel junction for novel spintronics applications: A novel magnetic tunnel junction which has four resistance states, instead of two states in existing magnetic tunnel junctions, may pave the way to novel spintronics devices, including multi-level magnetic August 21st, 2020

Spintronics: Faster data processing through ultrashort electric pulses July 3rd, 2020

Discoveries

An ionic forcefield for nanoparticles: Tunable coating allows hitch-hiking nanoparticles to slip past the immune system to their target November 27th, 2020

Russian scientists improve 3D printing technology for aerospace composites using oil waste November 27th, 2020

Phytoplankton disturbed by nanoparticles: Due to its antibacterial properties, nanosilver is used in a wide range of products from textiles to cosmetics; but nanosilver if present at high concentrations also disrupts the metabolism of algae that are essential for the aquatic food November 27th, 2020

Quantum nanodiamonds may help detect disease earlier: The quantum sensing abilities of nanodiamonds can be used to improve the sensitivity of paper-based diagnostic tests, potentially allowing for earlier detection of diseases such as HIV, according to a study led by UCL research November 27th, 2020

Announcements

Phytoplankton disturbed by nanoparticles: Due to its antibacterial properties, nanosilver is used in a wide range of products from textiles to cosmetics; but nanosilver if present at high concentrations also disrupts the metabolism of algae that are essential for the aquatic food November 27th, 2020

Quantum nanodiamonds may help detect disease earlier: The quantum sensing abilities of nanodiamonds can be used to improve the sensitivity of paper-based diagnostic tests, potentially allowing for earlier detection of diseases such as HIV, according to a study led by UCL research November 27th, 2020

One-way street for electrons: Scientists observe directed energy transport between neighbouring molecules in a nanomaterial November 27th, 2020

New insights into memristive devices by combining incipient ferroelectrics and graphene November 27th, 2020

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers/Posters

Russian scientists improve 3D printing technology for aerospace composites using oil waste November 27th, 2020

Phytoplankton disturbed by nanoparticles: Due to its antibacterial properties, nanosilver is used in a wide range of products from textiles to cosmetics; but nanosilver if present at high concentrations also disrupts the metabolism of algae that are essential for the aquatic food November 27th, 2020

Quantum nanodiamonds may help detect disease earlier: The quantum sensing abilities of nanodiamonds can be used to improve the sensitivity of paper-based diagnostic tests, potentially allowing for earlier detection of diseases such as HIV, according to a study led by UCL research November 27th, 2020

One-way street for electrons: Scientists observe directed energy transport between neighbouring molecules in a nanomaterial November 27th, 2020

Photonics/Optics/Lasers

Order in the disorder: density fluctuations in amorphous silicon discovered October 30th, 2020

CEA-Leti to Build Quantum-Photonics Platform to Ensure Ultra-Secure Data for Finance, Energy, Defense and Other Industries : Project Will Build Demonstrators for Transmitting and Receiving Qubits and Focus on Integrating the Technology in a Unique Platform to Address Quantum Comp October 30th, 2020

Revealing the reason behind jet formation at the tip of laser optical fiber October 16th, 2020

Surface waves can help nanostructured devices keep their cool October 12th, 2020

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project