Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A 'dirt cheap' magnetic field sensor from 'plastic paint'

13.06.2012
Spintronic device uses thin-film organic semiconductor

University of Utah physicists developed an inexpensive, highly accurate magnetic field sensor for scientific and possibly consumer uses based on a "spintronic" organic thin-film semiconductor that basically is "plastic paint."

The new kind of magnetic-resonance magnetometer also resists heat and degradation, works at room temperature and never needs to be calibrated, physicists Christoph Boehme, Will Baker and colleagues report online in the Tuesday, June 12 edition of the journal Nature Communications.

The magnetic-sensing thin film is an organic semiconductor polymer named MEH-PPV. Boehme says it really is nothing more than an orange-colored "electrically conducting, magnetic field-sensing plastic paint that is dirt cheap. We measure magnetic fields highly accurately with a drop of plastic paint, which costs just as little as drop of regular paint."

The orange spot is only about 5-by-5 millimeters (about one-fifth inch on a side), and the part that actually detects magnetic fields is only 1-by-1 millimeters. This organic semiconductor paint is deposited on a thin glass substrate which then is mounted onto a circuit board with that measures about 20-by-30 millimeters (about 0.8 by 1.2 inches).

The new magnetic field sensor is the first major result to come out of the new Materials Research Science and Engineering Center launched by the University of Utah last September: a six-year, $21.5 million program funded by the National Science Foundation, the Utah Science Technology and Research initiative and the university.

University of Utah physics professor Brian Saam, one of the center's principal investigators, says the new magnetometer "is viewed widely as having exceptional impact in a host of real-world science and technology applications."

Boehme is considering forming a spinoff company to commercialize the sensors, on which a patent is pending. In the study, the researchers note that "measuring absolute magnetic fields is crucial for many scientific and technological applications."

As for potential uses in consumer products, Boehme says it's difficult to predict what will happen, but notes that existing, more expensive magnetic-field sensors "are in many, many devices that we use in daily life: phones, hard drives, navigation devices, door openers, consumer electronics of many kinds. However, Joe Public usually is not aware when he uses those sensors."

"There are sensors out there already, but they're just not nearly as good – stable and accurate – and are much more expensive to make," Saam says.

Boehme believes the devices could be on the market in three years or less – if they can be combined with other new technology to make them faster. Speed is their one drawback, taking up to a few seconds to read a magnetic field.

Boehme, the study's senior author, conducted the research with University of Utah physics doctoral students Will Baker (the first author), Kapildeb Ambal, David Waters and Kipp van Schooten; postdoctoral researcher Hiroki Morishita; physics undergraduate student Rachel Baarda; and two physics professors who remain affiliated with the University of Utah after moving elsewhere: Dane McCamey of the University of Sydney, Australia, and John Lupton of the University of Regensburg, Germany.

The study was funded by the U.S. Department of Energy, National Science Foundation, David and Lucile Packard Foundation and Australian Research Council.

Sensor Based on Organic Spintronics

The sensors are based on a field of science named spintronics, in which data is stored both electronically in the electrical charges of electrons or atomic nuclei and in what is known as the "spin" of those subatomic particles.

Described simply, spin makes a particle behave like a tiny bar magnet that is pointed up or down within an electron or a nucleus. Down can represent 0 and up and represent 1, similar to how in electronics no charge represents 0 and a charge represents 1. Spintronics allows more information – spin and charge – to be used than electronics, which just uses charge.

The new magnetic field sensor paint contains negatively charged electrons and positively charged "holes" that align their spins parallel or not parallel in the absence or presence of a magnetic field – but only if radio waves of a certain frequency also are applied to the semiconductor paint.

So an electrical current is applied to the new device. Electrical contacts in the device act as tiny broadcast antennas to bombard the plastic paint with radio waves, which the researchers gradually change in frequency. If a magnetic field is present, the spins in the polymer paint will flip when the frequency of the radio waves matches the magnetic field. The change of spin in the paint is converted to an electrical current the researchers then read to determine magnetic field strength.

Because the paint is an organic polymer, the sensor is known as an organic spintronics device.

Device Works Even if 'Old and Crusty'

The new magnetometer can detect magnetic fields ranging from 1,000 times weaker than Earth's magnetic field to tens of thousands times stronger – a range that covers intermediate to strong magnetic fields, Boehme says.

He says the new magnetometer cannot measure very weak magnetic fields, which now are measured by devices known as SQUIDS. It can measure strong magnetic fields, and although conventional magnetic resonance devices do that very well, they are bulky and expensive – such as those used in medical MRI machines – so the low cost and small size of the new magnetometers may give them some advantages. But the major use of the new devices is for intermediate strength magnetic fields, for which no existing device works as well, Boehme says.

Boehme's new sensor is known as an organic magnetic resonance magnetometer or OMRM. Its one disadvantage is it is slow, taking up to a few seconds to detect a magnetic field. Boehme hopes to combine his technology with similar developing magnetometer technology known as an organic magnetoresistant sensor, or OMAR, which is more than 100 times faster but requires calibration, isn't very accurate, detects only weak to moderate magnetic fields and is vulnerable to temperature fluctuations and material degradation.

The new device "can literally get old and crusty, and as long as it can carry a detectable current, the magnetic field can be measured accurately," Boehme says.

Boehme says new experiments will determine how much smaller the 1-square-millimeter sensing area can be made and still have it accurately detect magnetic fields. He is aiming for 1 million times smaller: "It's a matter of microfabrication."

University of Utah Communications
201 Presidents Circle, Room 308
Salt Lake City, Utah 84112-9017
(801) 581-6773 fax: (801) 585-3350

Lee Siegel | EurekAlert!
Further information:
http://www.utah.edu

More articles from Power and Electrical Engineering:

nachricht Failures in power grids: Dynamically induced cascades
25.05.2018 | Technische Universität Dresden

nachricht Beyond the limits of conventional electronics: stable organic molecular nanowires
24.05.2018 | Tokyo Institute of Technology

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: Powerful IT security for the car of the future – research alliance develops new approaches

The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.

Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

In focus: Climate adapted plants

25.05.2018 | Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

 
Latest News

In focus: Climate adapted plants

25.05.2018 | Event News

Flow probes from the 3D printer

25.05.2018 | Machine Engineering

Less is more? Gene switch for healthy aging found

25.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>