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PREPARATION AND CHARACTERIZATION OF RARE EARTH TRANSITION METAL FILMS AND MULTILAYERS

Objective

Improved methods of thin film preparation, including laser ablation deposition. Development of new techniques for the magnetic characterization of thin films, including 57Fe depth sensitive conversion electro Mosshauer spectroscopy (DCEMS) and bulk magnetic property determination using SQUID magnetometry and the KERR effect. Preparation of thin film magnetic materials, including studies on surface magnetization effects, production of perpendicular anisotropy and ferro- and anti-ferro magnetic layer coupling The scientific and technical benefits are related to the development of novel thin film deposition techniques, including laser evaporation for the preparation of new magnetic materials. Substantial economic benefits could accrue, especially in the field of magnetic recording, permanent magnets, soft magnetic applications.
The overall objectives include improved methods of thin film preparation, including laser ablation deposition, development of new techniques for the magnetic characterisation of thin films, including iron 57 depth sensitive conversion electron Mossbauer spectroscopy and bulk magnetic property determination using SQUID magnetometry and the Kerr effect, preparation of thin film magnetic materials, for applications (magnetic recording, permanent magnets, soft magnetic applications).
Rare earth(R) transition metal(M) multilayers have been prepared by different techniques. High quality films have been obtained using laser ablation deposition. Resistively heated evaporation cells have been developed for the preparation of materials with a high melting temperature. Digital channel electron multiplier (DCEM) spectrometers have been built and used for the characterisation of R iron multilayers. A transverse Kerr effect magnetometer has been built. It is working in an entirely automatic mode, from 15 K to 300 K and in a maximum magnetic field of 2 T. The magnetooptical properties of R nickel and R cobalt amorphous films have been studied. Novel magnetisation processes have been observed in R cobalt/R cobalt/R cobalt sandwich films, associated with creation or annihilation of domain walls at the interface between individual layers. Perpendicular anistropy has been obtained in iron terbium multilayers resulting from the low symmetry environment for terbium atoms close to the interface.

Laser ablation depostion, a versatile technique for the preparation of metallic magnetic thin films, has been developed. The main experimental problems with this technique have been analyzed and solutions to them have been found.
A transverse Kerr effect magnetometer for magnetic characterization of thin films has been constructed with unique performance in terms of vacuum, temperatrue and magnetic fields.
Conversion electron Mossbauer spectrometers have been built for local probing of iron magnetism in thin films.
A new category of thin film materials has been discovered. These are rare earth cobalt sandwich films which constitute macroscopic ferrimagnets. A new type of wall has been shown to exist in these systems. Under certain experimental conditions it has been shown that a large magnetic susceptibility may exist which is an important property for various types of sensors.
Iron/terbium multilayers and iron silicide/silicon multilayers have been shown to exhibit perpendicular magnetic anisotropy with potential for magnetic recording applications.
THE RESEARCH PROJECT CONCERNS THE PREPARATION AND CHARACTERIZATION OF RARE EARTH-TRANSITION METAL MAGNETIC THIN FILMS. THE GOALS OF THE PROJECT ARE THE FOLLOWING :

- IMPROVEMENT OF THE METHODS OF THIN FILM PREPARATION, INCLUDING THE NEW TECHNIQUE OF LASER EVAPORATION, FOR THE SPECIAL CONDITIONS OF RARE-EARTH AND TRANSITION METAL ALLOYS.
- DEVELOPMENT OF NEW TECHNIQUES FOR THE MAGNETIC CHARACTERIZATION OF THIN FILMS, INCLUDING FE DEPTH CONVERSION ELECTRON MOESSBAUER SPECTROSCOPY (DCEMS) AND ITS APPLICATION TO RARE-EARTH NUCLEI AND BULK MAGNETIC PROPERTY DETERMINATIONS USING SQUID MAGNETOMETRY AND THE KERR EFFECT.
- PREPARATION OF NEW THIN FILM MAGNETIC MATERIALS, INCLUDING STUDIES ON SURFACE MAGNETISATION EFFECTS, PRODUCTION OF PERPENDICULAR ANISOTROPY AND FERRO- AND ANTI-FERRO MAGNETIC LAYER COUPLING.

A FULL TECHNICAL COLLABORATION BETWEEN 6 RESEARCH ORGANISATIONS IN 3 EEC COUNTRIES IS ENVISAGED.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE
Address
Avenue Des Martyrs 25
38042 Grenoble
France

Participants (5)

Commissariat à l'Energie Atomique (CEA)
France
Address
Centre D'études De Grenoble Avenue Des Martyrs
38041 Grenoble
ISA RIBER
Spain
UNIUNIVERSIDAD DE OVIEDO
Spain
Address

Oviedo
UNIVERSIDAD DE BARCELONA
Spain
Address

Barcelona
Universität Gesamthochschule Duisburg
Germany
Address
Lotharstraße 65
4100 Duisburg