Featured Research

from universities, journals, and other organizations

Using A Magnet To Tune A Magnet

Date:
August 2, 2007
Source:
University College London
Summary:
Scientists have found a way to switch a material's magnetic properties from "hard" to "soft" and back again -- something which could lead to new ways of controlling electromagnetic devices. The research shows how a magnet can be "tuned" by subjecting it to a second magnetic field, perpendicular to the original.

Domain wall pattern for a ferromagnet. The technical use of the magnet is determined by the ease with which the walls can be moved, or equivalently, by the force with which they are pinned. Strong pinning gives a hard magnet, soft pinning a soft magnet. The distance between the walls is 100 nanometers or 10 millionths of a centimeter.
Credit: Y-A. Soh and G. Aeppli

An international research team, led by scientists at the London Centre for Nanotechnology (LCN), has found a way to switch a material's magnetic properties from 'hard' to 'soft' and back again -- something which could lead to new ways of controlling electromagnetic devices. The research will appear in the journal Nature on August 2nd and shows how a magnet can be 'tuned' by subjecting it to a second magnetic field, perpendicular to the original.

Related Articles


Magnets can be classified by their 'hard' or 'soft' magnetic properties. Hard magnets, sometimes called 'permanent' magnets, have fixed or 'pinned' domain walls which mean the material stays magnetised for a long time. Soft magnets have moveable domain walls that can be easily flipped. These materials exhibit impermanent magnetic properties.

Professor Gabriel Aeppli, Director of the LCN and a senior member of the research team, explained the significance of the research: "Whether a magnet is hard or soft determines what you can use it for. Typically, you would use a permanent magnet to fix a note to the door of your refrigerator because you want it to stay there for a long time. On the other hand, you might use a soft magnet in a motor or transformer because it would be better at adapting to the rapid changes in alternating current and would dissipate much less energy than a hard magnet.

"It is very rare to be able to continuously tune wall pinning in a magnet but we have now shown how it can be done in a model magnet at a low temperature. In the process, we demonstrate a new route to applications of magnets at higher temperatures and show how chemical disorder at the nanometre (one billionth of a meter) scale can have a huge effect on the properties of a macroscopic (centimetre scale) magnet."

Most physical and biological systems can be thought of as disordered. Semiconductors rely on randomly placed impurities for their electrical properties and uses, while the chemical and structural impurities in magnets determine the domain wall pinning and therefore how easily their polarity can be changed.

"From a theoretical point of view, it's been really interesting for us to see the properties of a large, disordered system being dominated to such an extent by a rare configuration of impurities," says Professor Aeppli. "Unlike biological systems, in materials science we are used to seeing behaviour which is dominated by the average characteristics of the system. Here we can observe the massive influence of a miniscule number of chemical and structural defects."

Work at the London Centre for Nanotechnology was funded by the UK Engineering and Physical Sciences Research Council and a Wolfson-Royal Society Research Merit Award. Additional research was also carried out at the University of Chicago.


Story Source:

The above story is based on materials provided by University College London. Note: Materials may be edited for content and length.


Cite This Page:

University College London. "Using A Magnet To Tune A Magnet." ScienceDaily. ScienceDaily, 2 August 2007. <www.sciencedaily.com/releases/2007/08/070801161504.htm>.
University College London. (2007, August 2). Using A Magnet To Tune A Magnet. ScienceDaily. Retrieved October 31, 2014 from www.sciencedaily.com/releases/2007/08/070801161504.htm
University College London. "Using A Magnet To Tune A Magnet." ScienceDaily. www.sciencedaily.com/releases/2007/08/070801161504.htm (accessed October 31, 2014).

Share This



More Matter & Energy News

Friday, October 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

EU, Russia, Ukraine Seal Breakthrough Gas Accord

EU, Russia, Ukraine Seal Breakthrough Gas Accord

AFP (Oct. 31, 2014) Russia agrees to resume gas deliveries to war-torn Ukraine through the winter in an EU-brokered, multi-billion dollar deal signed by the three parties in Brussels. Duration: 01:10 Video provided by AFP
Powered by NewsLook.com
Relief After “gas War” Is Averted

Relief After “gas War” Is Averted

Reuters - Business Video Online (Oct. 31, 2014) A gas war between Russia and Ukraine has been averted. But as Hayley Platt reports a deal was only reached after Kiev's western creditors agreed to partly funding the deal. Video provided by Reuters
Powered by NewsLook.com
Jaguar Land Rover Opens $800 Million Factory in Britain

Jaguar Land Rover Opens $800 Million Factory in Britain

AFP (Oct. 30, 2014) British luxury car manufacturer Jaguar Land Rover opened a $800 million engine manufacturing centre in western England, creating 1,400 jobs. Duration: 00:45 Video provided by AFP
Powered by NewsLook.com
SkyCruiser Concept Claims to Solve Problem With Flying Cars

SkyCruiser Concept Claims to Solve Problem With Flying Cars

Buzz60 (Oct. 30, 2014) A start-up company called Krossblade says its SkyCruiser concept flying car solves the problem with most flying car concepts. Mara Montalbano (@maramontalbano) explains. Video provided by Buzz60
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins