‘Quantum material’ has shark-like ability to detect small electrical signals

Shark. Photo by Pixabay.

12/18/2017 |

A “quantum material” that mimics a shark’s ability to detect the minute electric fields of small prey has been shown to perform well in ocean-like conditions, with potential applications from defense to marine biology.

The material maintains its functional stability and does not corrode after being immersed in saltwater, a prerequisite for ocean sensing. Surprisingly, it also functions well in the cold, ambient temperatures typical of seawater, says Shriram Ramanathan, a Purdue professor of materials engineering.

From left, Purdue University doctoral student Derek Schwanz, professor Shriram Ramanathan and postdoctoral research associate Zhen Zhang, have led work to develop a sensor that mimics a shark’s “sixth sense.” (Purdue University image/Marshall Farthing)

Such a technology might be used to study ocean organisms and ecosystems and to monitor the movement of ships for military and commercial maritime applications.

“So, it has potentially very broad interest in many disciplines,” says Ramanathan, who led research to develop the sensor, working with a team that included Purdue postdoctoral research associate Zhen Zhang and graduate student Derek Schwanz.

Findings are detailed in a research paper appearing online Dec. 18 in the journal Nature. The paper’s lead authors were Zhang and Schwanz, working with colleagues at Argonne National Laboratory, Rutgers University, the National Institute of Standards and Technology, the Massachusetts Institute of Technology, the Canadian Light Source at the University of Saskatchewan, Columbia University, and the University of Massachusetts. A complete list of co-authors is included in the abstract.

The new sensor was inspired by an organ near a shark’s mouth called the ampullae of Lorenzini, which is capable of detecting small electric fields from prey animals.

“This organ is able to interact with its environment by exchanging ions from seawater, imparting the so-called sixth sense to sharks,” Zhang says.

The organ contains a jelly that conducts ions from seawater to a specialized membrane located at the bottom of the ampulla. Sensing cells in the membrane allow the shark to detect bioelectric fields emitted by prey fish.

The new sensor is made of a material called samarium nickelate, which is a quantum material, meaning its performance taps into quantum mechanical interactions. Samarium nickelate is in a class of quantum materials called strongly correlated electron systems, which have exotic electronic and magnetic properties.

Because this material can conduct protons very fast, the researchers wondered whether they might develop a sensor that mimics the shark’s organ.

“We have been working on this for a few years,” Ramanathan says. “We show that these sensors can detect electrical potentials well below one volt, on the order of millivolts, which is comparable to electric potentials emanated by marine organisms. The material is very sensitive. We calculated the detection distance of our device and find a similar length scale to what has been reported for electroreceptors in sharks.”

A YouTube video is available at https://youtu.be/f3UsD-1qGkE:

Writer: Emil Venere, http://bit.ly/2lWoYlD