Physicists find enhanced fluctuations in nanomagnets

September 6, 2013, New York University

NYU physicists have discovered that nanomagnets—a billionth of a meter in size—with a preferred up or down magnetization are sensitive to heating or cooling, more than expected.

Their findings, which appear in the journal Physical Review B Rapid Communication, suggest that a widely used model to describe the reversal of nanomagnets needs to be modified to account for temperature-dependent changes in the properties of the materials.

It is known that nanomagnets never switch at the same field each time – rather, random fluctuations in thermal energy generate a distribution of switching fields. But what's less clear is the origin of this phenomenon.

Developing a firmer understanding of the "activation energy" of nanomagnets is important in designing for magnetic memory-, such as in hard-disk drives and magnetic random access memories, in which can lead to data loss.

In their study, conducted in the laboratory of NYU physicist Andrew Kent, the researchers used a common approach to detect the activation energy barrier by measuring the distribution of switching fields across a wide temperature range.

The researchers discovered that changes in temperature were accompanied by changes in the height of the activation energy barrier. This resulted in a breakdown of the standard model, which assumes that the activation energy is temperature independent. This assumption works in earlier studies conducted over a limited range of temperatures. A modified model that considers the of the material characteristics fits the data well.

Explore further: Physicists light 'magnetic fire' to reveal energy's path

More information:

Related Stories

Physicists light 'magnetic fire' to reveal energy's path

May 13, 2013

New York University physicists have uncovered how energy is released and dispersed in magnetic materials in a process akin to the spread of forest fires, a finding that has the potential to deepen our understanding of self-sustained ...

Magnetic charge crystals imaged in artificial spin ice

August 28, 2013

A team of scientists has reported direct visualization of magnetic charge crystallization in an artificial spin ice material, a first in the study of a relatively new class of frustrated artificial magnetic materials-by-design ...

Recommended for you

Smallest ever sieve separates atoms

March 20, 2018

Researchers at The University of Manchester have discovered that the naturally occurring gaps between individual layers of two-dimensional materials can be used as a sieve to separate different atoms.

Quantum bits in two dimensions

March 20, 2018

Two novel materials, each composed of a single atomic layer and the tip of a scanning tunneling microscope, are the ingredients for a novel kind of quantum dot. These extremely small nanostructures allow delicate control ...

Rubbery carbon aerogels greatly expand applications

March 19, 2018

Researchers have designed carbon aerogels that can be reversibly stretched to more than three times their original length, displaying elasticity similar to that of a rubber band. By adding reversible stretchability to aerogels' ...

Scientists have a new way to gauge the growth of nanowires

March 19, 2018

In a new study, researchers from the U.S. Department of Energy's (DOE) Argonne and Brookhaven National Laboratories observed the formation of two kinds of defects in individual nanowires, which are smaller in diameter than ...

Plasmons triggered in nanotube quantum wells

March 16, 2018

A novel quantum effect observed in a carbon nanotube film could lead to the development of unique lasers and other optoelectronic devices, according to scientists at Rice University and Tokyo Metropolitan University.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.