Scientists find X-rays can cause reversible resistance changes

May 07, 2014 by Jared Sagoff
Argonne's Advanced Photon Source.

(Phys.org) —Usually, when we think of a device that has defects, it means it's time to throw it out. However, for several types of materials, imperfections are what actually make them function in the first place. Finding ways to control defects in a material without irrevocably damaging it could yield new information in the quest for an array of improved devices.

Synchrotron X-rays are frequently used to image a wide range of different materials, but they can also cause chemical changes as well. In a new study, researchers at the U.S. Department of Energy's Argonne National Laboratory looked at how a material's electrical resistance changes when it is irradiated with these high-energy X-rays.

In the experiment, the researchers looked at titanium dioxide, a material known for exhibiting multiple resistive states induced by defect movement. This behavior, known as resistive switching, could offer scientists a mechanism that may hold the key to potential new computer memories and even artificial neurons, according to Argonne materials scientist Seungbum Hong, who led the study along with Argonne physicist Jung Ho Kim.

"It's not easy to make a nanoscale device that switches reliably between resistive states," Hong said. "In order to design reliable resistive switching materials, you need to understand and control the defect at the nanoscale."

When the cell was exposed to the X-rays generated by Argonne's Advanced Photon Source, the scientists found the existence of a photovoltaic-like effect, which changes the resistance by orders of magnitude, depending on the intensity of the oncoming X-rays. This effect, combined with an X-ray irradiation-induced phase transition, triggers a non-volatile reversible resistance change – that is, the change in resistance can be observed even after the X-rays are turned off.

"This result was somewhat serendipitous, in that people had known that X-rays could damage these , but they hadn't been looking for this kind of reversible change," Kim said.

Explore further: Promising new alloy for resistive switching memory

More information: "X-ray Irradiation Induced Reversible Resistance Change in Pt/TiO2/Pt Cells." Seo Hyoung Chang, Jungho Kim, Charudatta Phatak, Kenneth D'Aquila, Seong Keun Kim, Jiyoon Kim, Seul Ji Song, Cheol Seong Hwang, Jeffrey A. Eastman, John W. Freeland, and Seungbum Hong. ACS Nano 2014 8 (2), 1584-1589. DOI: 10.1021/nn405867p

add to favorites email to friend print save as pdf

Related Stories

Promising new alloy for resistive switching memory

Sep 20, 2013

Memory based on electrically-induced "resistive switching" effects have generated a great deal of interest among engineers searching for faster and smaller devices because resistive switching would allow ...

Recommended for you

A crystal wedding in the nanocosmos

2 hours ago

Researchers at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), the Vienna University of Technology and the Maria Curie-Skłodowska University Lublin have succeeded in embedding nearly perfect semiconductor ...

PPPL studies plasma's role in synthesizing nanoparticles

Jul 22, 2014

DOE's Princeton Plasma Physics Laboratory (PPPL) has received some $4.3 million of DOE Office of Science funding, over three years, to develop an increased understanding of the role of plasma in the synthesis ...

User comments : 0