Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Thermal treatment for magneto-resistant materials design

09.07.2003


Reader heads of compact discs and computer hard discs or position and magnetic field sensors are some of the applications of magneto-resistant materials, which are normally obtained by costly methods. Precisely in order to solve this problem, university teacher María Luisa Fernández-Gubieda Ruiz, of the University of the Basque Country, is carrying out research into developing a simpler and more effective method for the preparation of these materials, based on their undergoing thermal treatment. The lecturer explained the new method at a seminar recently given at the Department of Physics at the Public University of Navarre.



Granular solids

Fernández-Gubieda explained that magneto-resistance is the change in resistance manifested by certain materials when subjected to a magnetic field. These changes, she added, can be of great importance and in some systems can reach a variation of up to 40 or 50 per cent.


She explained how, at the beginning of the 90’s, the discovery of huge magneto-resistance in granular multilayers and solids sparked enormous interest both for their peculiar magnetic and transfer properties, as for their possible technological applications as magnetic reading reader heads for very high density and velocity reading devices.

Concretely, Fernández-Gubieda’s research has centred on granular solids which are composed of magnetic particles (for example, iron, cobalt, nickel) saturated in a non-magnetic matrix (for example, copper or silver). With these materials, the professor commented, the origin of the magneto-resistance is principally due to the magnetic scattering of the interface carriers, between the magnetic particles and the matrix. Thus, this quality fundamentally depends on the size of the magnetic particles, of their composition and of the interaction between them.

Thermal treatment
To understand the mechanisms controlling magneto-resistance, Fernández-Gubieda carried out an exhaustive study on the development of the microstructure of the granular solids by means of thermal treatment and analysed its influence on the magnetic properties and magneto-transfer.

The study of the structural evolution was carried out using two complementary techniques: high resolution X-ray diffraction and X-ray absorption spectroscopy, using the Sincrotron at Grenoble and the nuclear reactor at Laue-Langevin, both in France.

As a result of this research, Profesor Fernández-Gubieda observed how, at temperatures greater than 500ºC, a re-dissolution of cobalt and copper was produced, giving rise to an increase in the roughness at the interface between a the nanometric particles of cobalt and the copper matrix, which, in turn, produced the drop in magneto-resistance, she concluded.

Garazi Andonegi | Basque research
Further information:
http://www.basqueresearch.com

More articles from Materials Sciences:

nachricht Looking at linkers helps to join the dots
10.07.2020 | King Abdullah University of Science & Technology (KAUST)

nachricht Goodbye Absorbers: High-Precision Laser Welding of Plastics
10.07.2020 | Fraunhofer-Institut für Lasertechnik ILT

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: The spin state story: Observation of the quantum spin liquid state in novel material

New insight into the spin behavior in an exotic state of matter puts us closer to next-generation spintronic devices

Aside from the deep understanding of the natural world that quantum physics theory offers, scientists worldwide are working tirelessly to bring forth a...

Im Focus: Excitation of robust materials

Kiel physics team observed extremely fast electronic changes in real time in a special material class

In physics, they are currently the subject of intensive research; in electronics, they could enable completely new functions. So-called topological materials...

Im Focus: Electrons in the fast lane

Solar cells based on perovskite compounds could soon make electricity generation from sunlight even more efficient and cheaper. The laboratory efficiency of these perovskite solar cells already exceeds that of the well-known silicon solar cells. An international team led by Stefan Weber from the Max Planck Institute for Polymer Research (MPI-P) in Mainz has found microscopic structures in perovskite crystals that can guide the charge transport in the solar cell. Clever alignment of these "electron highways" could make perovskite solar cells even more powerful.

Solar cells convert sunlight into electricity. During this process, the electrons of the material inside the cell absorb the energy of the light....

Im Focus: The lightest electromagnetic shielding material in the world

Empa researchers have succeeded in applying aerogels to microelectronics: Aerogels based on cellulose nanofibers can effectively shield electromagnetic radiation over a wide frequency range – and they are unrivalled in terms of weight.

Electric motors and electronic devices generate electromagnetic fields that sometimes have to be shielded in order not to affect neighboring electronic...

Im Focus: Gentle wall contact – the right scenario for a fusion power plant

Quasi-continuous power exhaust developed as a wall-friendly method on ASDEX Upgrade

A promising operating mode for the plasma of a future power plant has been developed at the ASDEX Upgrade fusion device at Max Planck Institute for Plasma...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Contact Tracing Apps against COVID-19: German National Academy Leopoldina hosts international virtual panel discussion

07.07.2020 | Event News

International conference QuApps shows status quo of quantum technology

02.07.2020 | Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

 
Latest News

X-ray scattering shines light on protein folding

10.07.2020 | Life Sciences

Looking at linkers helps to join the dots

10.07.2020 | Materials Sciences

Surprisingly many peculiar long introns found in brain genes

10.07.2020 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>