Discovery of new colossal magnetoresistance mechanism

Aug 28, 2012

A NIMS research group has discovered a new material, NaCr2O4, which displays a novel type of colossal magnetoresistance effect. The new material was developed by ultra-high pressure synthesis.

Materials in which electrical resistance changes by an order of magnitude when a magnetic field is applied are called colossal magnetoresistance (CMR) materials. Virtually all known CMR materials are oxides of manganese, and their CMR mechanism also depends on a special ferromagnetic-metallic phase of manganese ions. However, new CMR mechanisms and material search guidelines which do not rely on have been demanded.

In this research, a new material, NaCr2O4, was developed by ultra-high pressure synthesis, focusing on the following two points: (1) Calcium structures have both a 1-dimensional and a structure which displays magnetic frustration, and (2) oxides with tetravalent ions of Cr have a special .

It was found that a CMR effect occurs in NaCr2O4, which is not a ferromagnetic metal, but rather, is an antiferromagnetic semiconductor. Although the CMR effect appears over a wide temperature range, i.e., the entire temperature range below the magnetic , this is a CMR effect with a new mechanism, which has the novel feature of not displaying history effects with respect to temperature or the magnetic field.

This result has important implications for the search for CMR materials, as it is also necessary to consider the antiferromagnetic semiconductors, which had seemed unrelated to the CMR effect until now. The new mechanism proposed as a result of this research has the potential to become a new material search guideline, as the CMR effect can be considered to occur in the diverse structures of various transition metal compounds.

Explore further: New complex oxides could advance memory devices

add to favorites email to friend print save as pdf

Related Stories

'Colossal' Magnetic Effect Under Pressure

Jun 05, 2009

(PhysOrg.com) -- Millions of people today carry around pocket-sized music players capable of holding thousands of songs, thanks to the discovery 20 years ago of a phenomenon known as the “giant magnetoresistance ...

Recommended for you

New complex oxides could advance memory devices

Sep 17, 2014

The quest for the ultimate memory device for computing may have just taken an encouraging step forward. Researchers at The City College of New York led by chemist Stephen O'Brien have discovered new complex ...

Mechanical behavior of twinned aluminum revealed

Sep 15, 2014

A research group has discovered plasticity and work-hardening behaviors in twinned aluminum with incoherent twin boundaries by using in situ nanoindentation technique. The group's paper titled "In situ nanoindentation ...

Invisibility cloaks closer thanks to 'digital metamaterials'

Sep 15, 2014

The concept of "digital metamaterials" – a simple way of designing metamaterials with bizarre optical properties that could hasten the development of devices such as invisibility cloaks and superlenses – is reported in a paper published today in Nature ...

User comments : 0