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BALLISTIC MAGNETORESISTANCE SENSOR HEAD FOR MAGNETIC STORAGE

Objective

This project explores micro and nanotechnology processes for the formation of stable magnetic constrictions that exhibit ballistic magnetoresistance, which is up to one or two order of magnitude larger (1) than the giant magnetoresistance used in present magnetic reading, and are nanoconstrictions (vertical, planar), using local probes, electrochemistry electron microscopy and nanocontacts in this films (1) N. Garcia, M.Munoz and Y.-W. Zhao, Physical Review Letters 82, 2923 (1999) This project explores micro and nanotechnology processes for the formation of stable magnetic constrictions that exhibit ballistic magnetoresistance, which is up to one or two order of magnitude larger (1) than the giant magnetoresistance used in present magnetic reading, and are nanoconstrictions (vertical, planar), using local probes, electrochemistry electron microscopy and nanocontacts in this films (1) N. Garcia, M.Munoz and Y.-W. Zhao, Physical Review Letters 82, 2923 (1999).

OBJECTIVES
The objective of this project is to explore micro and nanotechnology fabrication procedures for the formation of stable magnetic constrictions. This is the first crucial step towards the development of magnetic reading heads and sensors of unprecedented sensitivity and resolution. Magnetic constrictions provine a ballistic, very large magnetoresistance (BMR) at a resistance in the kohm range and spacially confined to a few nm dimensions. The BMR can be up to two orders of magnitude larger that the giant magnetoresistance used at present. Also, theory for understanding spin scattering on domain walls in nanosystems as well shifting of domains walls under external magnetic field is needed.

DESCRIPTION OF WORK
A magnetic constriction exhibiting a BMR is based on quantum conduction and is essentially a nanometer sized, conductive connection of width comparable with the electron wavelenght and of length smaller than the electron mean free path between two conductive magnetic reservoirs of larger dimension. Quantum conduction and BMR in metal have so far been studied in semitransient configurations, e.g. moving two metallic pieces in or out of contact. Our goal is to produce constrictions in stable configurations employing micro and nanotechnology fabrication procedures. We envisage two promising approaches for fabrication: 1) Vertical structuring: nanoscopic indentation in a thin insulator, filled with the appropriate material providing the constriction. A variety of options for indentation, filling processes, and insulator layer will be considered; 2) Planar structuring of the constriction: we consider four options for the final nanostructuring of the constriction: local probes (AFM, STM, MFM, SNOM, etc.), electron microscopy, and thin films nanocontacts. Parallel to the experimental work, the theory is necessary for understanding of nanomagnetism and magnetic domains walls motion in nanostructures. This will also be developed.

Funding Scheme

ACM - Preparatory, accompanying and support measures

Coordinator

CONSEJO SUPERIOR DE INVESTIGACIONES CIENTIFICAS
Address
C/ Serrano 117
28006 Madrid
Spain

Participants (2)

RIJKSUNIVERSITEIT GRONINGEN
Netherlands
Address
Broerstraat 5
9712 CP Groningen
UNIVERSITAET BASEL
Switzerland
Address
Petersgraben 35
4003 Basel