Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Materials: Cubic cluster chills out


A gadolinium-based material that can be cooled by varying a magnetic field may be useful for cooling low-temperature sensors.

Magnetic refrigeration is attracting attention as an efficient way to chill sensitive scientific instruments. This refrigeration method exploits the magnetocaloric effect, in which an external magnetic field controls the temperature of a magnetic material.

The magnetic refrigerant contains a cubic structure made of two gadolinium ions (pink), two nickel ions (green) and four oxygen atoms (red), surrounded by 2-(hydroxymethyl)pyridine molecules.

Copyright : 2014 A*STAR Institute of Materials Research and Engineering

Effective magnetic refrigerants are often difficult to prepare, but now Andy Hor of the A*STAR Institute of Materials Research and Engineering and the National University of Singapore and his colleagues have created a powerful magnetic refrigerant that is easy to make in the lab [1].

Compounds with a large magnetocaloric effect typically contain atoms with many unpaired electrons, each of which generates its own tiny magnetic moment. During magnetic refrigeration, an external magnetic field forces these atomic magnetic moments to line up in the same direction. As the magnetism of the atoms becomes more ordered (which reduces the entropy of the system), the material’s temperature rises.

Once the heat has been removed by a flowing liquid or gas, the external magnetic field is reduced. This allows the atomic magnetic moments to become disordered again, cooling the material so that it can be used to draw heat from an instrument, before repeating the cycle.

Magnetic refrigerants commonly use the gadolinium(III) ion (Gd3+), because it has seven unpaired electrons. Most gadolinium complexes are made under harsh conditions or take a very long time to form, which limits their wider application. In contrast, the magnetic refrigerant developed by Hor and colleagues is remarkably easy to make.

The researchers simply mixed gadolinium acetate, nickel acetate and an organic molecule called 2-(hydroxymethyl)pyridine in an organic solvent at room temperature. After 12 hours, these chemicals had assembled themselves into an aggregate containing a cube-like structure of atoms at its heart (see image).

The team measured how an external magnetic field affected this ‘cubane’ material as the temperature dropped. Below about 50 K, they found that the material’s magnetization increased sharply, suggesting that it could be an effective magnetic refrigerant below this temperature.

The scientists then tested the effects of varying the external magnetic field at very low temperatures. They found that at 4.5 K, a large external field caused an entropy change that was close to the theoretical maximum for the system — and larger than most other magnetic refrigerants under similar conditions.

According to the team, the magnetocaloric effect of magnetic refrigerants has typically been enhanced by creating ever-larger clusters of metal atoms. In contrast, their cubane shows that much simpler aggregates, prepared under straightforward conditions, are promising as magnetic refrigerants.


1. Wang, P., Shannigrahi, S., Yakovlev, N. L., and Hor, T. S. A. Facile self-assembly of intermetallic [Ni2Gd2] cubane aggregate for magnetic refrigeration. Chemistry – An Asian Journal 8, 2943–2946 (2013).

Lee Swee Heng | Research SEA News
Further information:

Further reports about: A*STAR Magnetic Science aggregate chills electrons magnetism temperature tiny

More articles from Materials Sciences:

nachricht Coming to a monitor near you: A defect-free, molecule-thick film
27.11.2015 | University of California - Berkeley

nachricht Controlling Electromagnetic Radiation by Graphene
27.11.2015 | Universität Augsburg

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Climate study finds evidence of global shift in the 1980s

Planet Earth experienced a global climate shift in the late 1980s on an unprecedented scale, fuelled by anthropogenic warming and a volcanic eruption, according to new research published this week.

Scientists say that a major step change, or ‘regime shift’, in the Earth’s biophysical systems, from the upper atmosphere to the depths of the ocean and from...

Im Focus: Innovative Photovoltaics – from the Lab to the Façade

Fraunhofer ISE Demonstrates New Cell and Module Technologies on its Outer Building Façade

The Fraunhofer Institute for Solar Energy Systems ISE has installed 70 photovoltaic modules on the outer façade of one of its lab buildings. The modules were...

Im Focus: Lactate for Brain Energy

Nerve cells cover their high energy demand with glucose and lactate. Scientists of the University of Zurich now provide new support for this. They show for the first time in the intact mouse brain evidence for an exchange of lactate between different brain cells. With this study they were able to confirm a 20-year old hypothesis.

In comparison to other organs, the human brain has the highest energy requirements. The supply of energy for nerve cells and the particular role of lactic acid...

Im Focus: Laser process simulation available as app for first time

In laser material processing, the simulation of processes has made great strides over the past few years. Today, the software can predict relatively well what will happen on the workpiece. Unfortunately, it is also highly complex and requires a lot of computing time. Thanks to clever simplification, experts from Fraunhofer ILT are now able to offer the first-ever simulation software that calculates processes in real time and also runs on tablet computers and smartphones. The fast software enables users to do without expensive experiments and to find optimum process parameters even more effectively.

Before now, the reliable simulation of laser processes was a job for experts. Armed with sophisticated software packages and after many hours on computer...

Im Focus: Quantum Simulation: A Better Understanding of Magnetism

Heidelberg physicists use ultracold atoms to imitate the behaviour of electrons in a solid

Researchers at Heidelberg University have devised a new way to study the phenomenon of magnetism. Using ultracold atoms at near absolute zero, they prepared a...

All Focus news of the innovation-report >>>



Event News

Fraunhofer’s Urban Futures Conference: 2 days in the city of the future

25.11.2015 | Event News

Gluten oder nicht Gluten? Überempfindlichkeit auf Weizen kann unterschiedliche Ursachen haben

17.11.2015 | Event News

Art Collection Deutsche Börse zeigt Ausstellung „Traces of Disorder“

21.10.2015 | Event News

Latest News

Siemens to supply 126 megawatts to onshore wind power plants in Scotland

27.11.2015 | Press release

Two decades of training students and experts in tracking infectious disease

27.11.2015 | Life Sciences

Coming to a monitor near you: A defect-free, molecule-thick film

27.11.2015 | Materials Sciences

More VideoLinks >>>