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 First Juno science results supported by University of Leicester's Jupiter 'forecast'
26.05.2017 | University of Leicester

nachricht Measured for the first time: Direction of light waves changed by quantum effect
24.05.2017 | Vienna University of Technology

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: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

How herpesviruses win the footrace against the immune system

26.05.2017 | Life Sciences

Water forms 'spine of hydration' around DNA, group finds

26.05.2017 | Life Sciences

First Juno science results supported by University of Leicester's Jupiter 'forecast'

26.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>