Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A Glassy Look for Manganites

29.04.2014

Berkeley Lab Researchers at the ALS Observe Glass-like Behavior in the Electron-Spins of PCMO Crystals

Manganites – compounds of manganese oxides – show great promise as “go-to” materials for future electronic devices because of their ability to instantly switch from an electrical insulator to a conductor under a wide variety of external stimuli, including magnetic fields, photo-excitations and vibrational excitations. 


Ultrafast pulses of x-rays from Berkeley Lab’s Advanced Light Source revealed a glass-like re-ordering of electron-spin states in PCMO crystals as samples recovered from a photo-excited conductor state back to the insulator state. In this schematic, circles and lobes show manganese sites and orbitals with pink and blue colors representing opposite spin orientations

This ultrafast switching arises from the many different ways in which the electrons and electron-spins in a manganite may organize or re-organize in response to such external stimuli. Understanding the physics behind these responses is crucial for the future development of manganites.

In a recent study of praseodymium calcium manganite (PCMO) crystals, a model manganite system, researchers at Lawrence Berkeley National Laboratory (Berkeley Lab) discovered that under photo-stimulation the insulator/conductor switching, which depends primarily on charge-ordering, may be ultra-fast, but the re-ordering of electron-spin, upon which magnetic properties depend, is not. In fact, the re-ordering of spin in these materials actually exhibits a glass-like state, in which the restoration of crystalline order is substantially delayed.

“The electron-spins get trapped in a frustrated, disordered state, like cars trying to merge without road signs or lane markers, and can take multiple seconds, a comparatively very long time, to sort themselves out,” says Robert Schoenlein of Berkeley Lab’s Materials Sciences Division, one of the leaders of this study. “This separation of charge-ordering behavior from spin-ordering behavior may point the way to new approaches to manipulating spin effects for applications in switching and memory devices.”

Working at beamline 6.0.2 of Berkeley Lab’s Advanced Light Source (ALS), Schoenlein and a team that included Shuyun Zhou and  Yi-De Chuang probed spin-ordering in PCMO crystals using a technique called time-resolved resonant soft x-ray scattering spectroscopy (TR-RSXS). In this technique, they pelted PCMO samples with 70 picosecond (trillionths of a second) pulses of x-rays to capture a series of snapshots that revealed how electron-spin ordering is re-established as the samples recover from a photo-excited conductor state back to the insulator state.

“We found that the glass-like behavior of the electron-spins arise from the metastable state created by photo-excitation, a state characterized by spin disordered metallic droplets within the larger charge- and spin-ordered insulating domains,” says ALS staff scientist Chuang. “Comparison with time-resolved resistivity measurements suggests that the collapse of spin ordering is correlated with the insulator-to-metal transition, but the recovery of the insulating phase does not depend on the re-establishment of the spin ordering.”

Adds Zhou, “Our work provides a new perspective for revealing the fascinating physics hidden in the recovery dynamics of electronic ordering in correlated electron materials after transient photo-excitation, a prominent method for ultrafast manipulation of material properties. Since other transition metal oxides that exhibit intriguing emergent phenomena, such as the high-temperature superconducting cuprates, also have rich competing phases involving dynamic electronic orderings, we should be able to extend similar TR-RSXS studies to those systems as well.”

A paper reporting this research has been published in the journal Scientific Reports. The paper is entitled “Glass-like recovery of antiferromagnetic spin ordering in a photo-excited manganite Pr0.7Ca0.3MnO3.” Schoenlein, Chuang and Zhou are the corresponding authors.

Lynn Yarris | Eurek Alert!
Further information:
http://newscenter.lbl.gov/science-shorts/2014/04/28/a-glassy-look-for-manganites/

Further reports about: Laboratory conductor crystalline crystals electrons materials photo-excitation physics transition

More articles from Physics and Astronomy:

nachricht NASA's fermi finds possible dark matter ties in andromeda galaxy
22.02.2017 | NASA/Goddard Space Flight Center

nachricht Tune your radio: galaxies sing while forming stars
21.02.2017 | Max-Planck-Institut für Radioastronomie

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Positrons as a new tool for lithium ion battery research: Holes in the electrode

22.02.2017 | Power and Electrical Engineering

New insights into the information processing of motor neurons

22.02.2017 | Life Sciences

Healthy Hiking in Smart Socks

22.02.2017 | Innovative Products

VideoLinks
B2B-VideoLinks
More VideoLinks >>>