Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

On the Road to Mottronics

24.02.2014
Researchers at the Advanced Light Source Find Key to Controlling the Electronic and Magnetic Properties of Mott Thin Films

“Mottronics” is a term seemingly destined to become familiar to aficionados of electronic gadgets. Named for the Nobel laureate   Nevill Francis Mott, Mottronics involve materials – mostly metal oxides – that can be induced to transition between electrically conductive and insulating phases.


Epitaxial mismatches in the lattices of nickelate ultra-thin films can be used to tune the energetic landscape of Mott materials and thereby control conductor/insulator transitions.

If these phase transitions can be controlled, Mott materials hold great promise for future transistors and memories that feature higher energy efficiencies and faster switching speeds than today’s devices. A team of researchers working at Berkeley Lab’s Advanced Light Source (ALS) have  demonstrated the conducting/insulating phases of ultra-thin films of Mott materials can be controlled by applying an epitaxial strain to the crystal lattice.

"Our work shows how an epitaxial mismatch in the lattice can be used as a knot to tune the energetic landscape of Mott materials and thereby control conductor/insulator transitions,” says Jian Liu, a post-doctoral scholar now with Berkeley Lab’s Materials Sciences Division, who is the lead author on a paper describing this work in the journal Nature Communications. “Through epitaxial strain, we forced nickelate films containing only a few atomic layers into different phases with dramatically different electronic and magnetic properties. While some of these phases are not obtainable in conventional ways, we were able to produce them in a form that is ready for device development.”

The Nature Communications paper is titled “Heterointerface engineered electronic and magnetic phases of NdNiO3 thin films.” The corresponding author is Jak Chakhalian, a professor of physics at the University of Arkansas. Co-authors are Mehdi Kargarian, Mikhail Kareev, Ben Gray, Phil Ryan, Alejandro Cruz, Nadeem Tahir, Yi-De Chuang, Jinghua Guo, James Rondinelli, John Freeland and Gregory Fiete.

Nickel-based rare-earth perovskite oxides, or “nickelates,” are considered to be an ideal model for the study of Mott materials because they display strongly correlated electron systems that give rise to unique electronic and magnetic properties. Liu and his co-authors studied thin films of neodymium nickel oxide using ALS beamline 8.0.1, a high flux undulator beamline that produces x-ray beams optimized for the study of nanoscale materials and strongly correlated physics.

“ALS beamline 8.0.1 provides the high photon flux and energy range that are critical when dealing with nanoscale samples,” Liu says. “The state-of-the-art Resonant X-ray Scattering endstation has a high-speed, high-sensitivity CCD camera that makes it feasible to find and track diffraction peaks off a thin film that was only six nanometers thick.”

The transition between the conducting and insulating phases in nickelates is determined by various microscopic interactions, some of which favor the conducting phase, some which favor the insulating phase. The energetic balance of these interactions determines how easily electricity is conducted by electrons moving between the nickel and oxygen ions. By applying enough epitaxial strain to alter the space between these ions, Liu and his colleagues were able to tune this energetic balance and control the conducting/insulating transition. In addition, they   found strain could also be used to control the nickelate’s magnetic properties, again by exploiting the lattice mismatch.

“Magnetism is another hallmark of Mott materials that often goes hand-in-hand with the insulating state and is used to distinguish Mott insulators,” says Liu. “The challenge is that most Mott insulators, including nickelates, are antiferromagnets that macroscopically behave as non-magnetic materials. “At ALS beamline 8.0.1, we were able to directly track the magnetic evolution of our thin films while tuning the metal-to-insulator transition. Our findings give us a better understanding of the physics behind the magnetic properties of these nickelate films and point to potential applications for this magnetism in novel Mottronics devices.”

This research was primarily supported the U.S. Department of Energy’s Office of Science.

Lynn Yarris | EurekAlert!
Further information:
http://www.lbl.gov

Further reports about: Magnetic Properties Mottronics insulators interactions ions materials mismatch strain

More articles from Materials Sciences:

nachricht New method developed for timely detection of impending material failure
28.08.2015 | Universität Siegen

nachricht Soaking up carbon dioxide and turning it into valuable products
28.08.2015 | DOE/Lawrence Berkeley National Laboratory

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: OU astrophysicist and collaborators find supermassive black holes in quasar nearest Earth

A University of Oklahoma astrophysicist and his Chinese collaborator have found two supermassive black holes in Markarian 231, the nearest quasar to Earth, using observations from NASA's Hubble Space Telescope.

The discovery of two supermassive black holes--one larger one and a second, smaller one--are evidence of a binary black hole and suggests that supermassive...

Im Focus: What would a tsunami in the Mediterranean look like?

A team of European researchers have developed a model to simulate the impact of tsunamis generated by earthquakes and applied it to the Eastern Mediterranean. The results show how tsunami waves could hit and inundate coastal areas in southern Italy and Greece. The study is published today (27 August) in Ocean Science, an open access journal of the European Geosciences Union (EGU).

Though not as frequent as in the Pacific and Indian oceans, tsunamis also occur in the Mediterranean, mainly due to earthquakes generated when the African...

Im Focus: Self-healing landscape: landslides after earthquake

In mountainous regions earthquakes often cause strong landslides, which can be exacerbated by heavy rain. However, after an initial increase, the frequency of these mass wasting events, often enormous and dangerous, declines, in fact independently of meteorological events and aftershocks.

These new findings are presented by a German-Franco-Japanese team of geoscientists in the current issue of the journal Geology, under the lead of the GFZ...

Im Focus: FIC Proteins Send Bacteria Into Hibernation

Bacteria do not cease to amaze us with their survival strategies. A research team from the University of Basel's Biozentrum has now discovered how bacteria enter a sleep mode using a so-called FIC toxin. In the current issue of “Cell Reports”, the scientists describe the mechanism of action and also explain why their discovery provides new insights into the evolution of pathogens.

For many poisons there are antidotes which neutralize their toxic effect. Toxin-antitoxin systems in bacteria work in a similar manner: As long as a cell...

Im Focus: Fraunhofer IPA develops prototype of intelligent care cart

It comes when called, bringing care utensils with it and recording how they are used: Fraunhofer IPA is developing an intelligent care cart that provides care staff with physical and informational support in their day-to-day work. The scientists at Fraunhofer IPA have now completed a first prototype. In doing so, they are continuing in their efforts to improve working conditions in the care sector and are developing solutions designed to address the challenges of demographic change.

Technical assistance systems can improve the difficult working conditions in residential nursing homes and hospitals by helping the staff in their work and...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Networking conference in Heidelberg for outstanding mathematicians and computer scientists

20.08.2015 | Event News

Scientists meet in Münster for the world’s largest Chitin und Chitosan Conference

20.08.2015 | Event News

Large agribusiness management strategies

19.08.2015 | Event News

 
Latest News

Interstellar seeds could create oases of life

28.08.2015 | Physics and Astronomy

An ounce of prevention: Research advances on 'scourge' of transplant wards

28.08.2015 | Health and Medicine

Fish Oil-Diet Benefits May be Mediated by Gut Microbes

28.08.2015 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>