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GERCSI Zsolt
Poste : doctorant
Adresse E-mail : nom@satie.ens-cachan.fr
Adresse Postale : SATIE, 61 Avenue du Président Wilson
94235 Cachan Cedex
France
Numéro de téléphone : 01 47 40 21 09


Atteindre directement : Curriculum Thèmes de recherche Travaux et Publications (extraits)

Curriculum
Zsolt Gercsi est né le 30 avril 1978 a Békéscsaba en Hongrie. Il a commencé ses études superieures en 1996 à la faculté de sciences Eotvos Lorand (ELTE) à Budapest. Pendant les deux années 1997-1998, il a suivi en parallèle des cours à la faculté de metallurgie de Miskolc . Le 22 décembre 2001, il a soutenu sa thèse de mastere, dont le stage s'est déroulé au RISSPO (Research Institut for Solid State Physics and Optic) de Budapest. Il est doctorant à l'ENS de Cachan depuis le 1er janvier 2002. La soutenance de thèse est prévue fin 2004. Z. Gerci est actuellement post-doctorant à l'institut de sciences des matériaux de Tsukuba dans l'équipe du Pr. Hono.

Thèmes de Recherche
Rubans nanocristallins : Summary of Ph. D. thesis: The work deals with the induced anisotropy and the high temperature behavior of Co-based soft magnetic materials. For this purpose several alloy systems with different Co-content were planned and made by melt-spinning technique such as FeCoSiNbBCu, FeCoNbZrBCu, FeCoNbB etc. One part of the work is devoted to in-situ hysteresis measurements of the above mentioned alloys. A special set-up was designed and realized to obtain in-situ hysteresis loops during the whole heating-cooling annealing process. Depending on the amorphous precursor which is in either ferromagnetic or paramagnetic state at the temperature of precipitating nanocrystalline phase, very different evaluation of magnetic properties was obtained. Blocked superparamagnetic behavior (sharpe increase of Hc) caused by different physical origin such as high K1 or Ms was found in cases with low Curie temperature of amorphous phase. Progression of crystallized fraction as annealing time advances, the whole magnetic system becomes coupled (Hc decreases) and the RAM model takes place. For samples where TCamorph > TX1 (for some cases TCamorph < TX1) both phases can be magnetically coupled during the whole crystallization process. Previously reported phenomena, e. g. - magnetic hardening of amorphous-nanocrystalline system for the period of heat treatments were also found and investigated. Further aim of this thesis was to investigate the effect of Co addition on induced anisotropy in these alloys by magnetic and/or stress annealing. Elongation of ribbons (creeping rate) during stress annealing was in-situ recorded and systematically studied (effect of different annealing time/temperature on induced anisotropy). Defence of thesis is planned at the end of 2004.
Click here to download (in .avi format ~2.5Mb) how the magnetic properties change (in-situ) in Fe58Co25Nb7B9Cu1 alloy during thermal annealing (from amorphous to nanocrystalline state).

Click here to download (in .avi format ~2.5Mb) how the magnetic properties change (in-situ) in Fe78Si9Nb3B9Cu1 (Finemet type)alloy during thermal annealing (from amorphous to nanocrystalline state).



All these videos are based on real measurements using Microcal Origin 6.0 scripts with Mplayer codecs. If you want to know more about the method e-mail me.


Travaux et Publications (extraits)
Structural studies of stress annealed Co21Fe64-xNbxB15 alloys :
- S. N. KANE - S.S Khinchi - Zsolt GERCSI - Ajay GUPTA - Lajos Karoly VARGA - Frédéric MAZALEYRAT
- Reviews on advanced materials science 18 (2008) pp. 572-575.
 
Influence of Composition and Thermal Treatments on Structural, Magnetic and Magnetotransport Properties of (FE 100-x Co x) 78 Si9Nb3B9Cu1 Alloys :
- S. N. KANE - Zsolt GERCSI - Frédéric MAZALEYRAT - Lajos Karoly VARGA - M. COÏSSON - P. TIBERTO - F. VINAI - F. CELEGATO - Y.H JEONG
- J. Korean Phys. Soc. 53 (2008) pp. 3624-3639
 
Surface analysis of FeCoNbCub metallic glasses using miniaturised Mössbauer spectrometer 'MIMOS' :
- S. N. KANE - Zsolt GERCSI - Frédéric MAZALEYRAT - D. Rodionov - B. Bernhardt - G. Klingelhöfer
- Journal of Non-Crystalline Solids 353 3587-3589
 
Influence of annealing on high frequency magnetotransport properties of melt-spun FeCoNbB alloys :
- S. N. KANE - Zsolt GERCSI - Frédéric MAZALEYRAT - Lajos Karoly VARGA - Ajay GUPTA - M. COÏSSON - P. TIBERTO - F. VINAI - F. CELEGATO
- Journal of Non-Crystalline Solids, 353 (2007) 3099-3102
 
The influence of size on coercive field of ultra soft magnetic materials :
- Lajos Karoly VARGA - Zsolt GERCSI - Gy. KOVACS - Frédéric MAZALEYRAT
- J. Magn. Magn. Mat. in press
 
"Mossbauer and magnetic studies of (Fe1001-xCox)62 Nb&B30 (X=0,33,50) alloys" :
- S. N. KANE - Ajay GUPTA - Zsolt GERCSI - Frédéric MAZALEYRAT - Lajos Karoly VARGA
- J. Magn. Magn. Mater. 292 (2005) pp447-452
 
The influence of size on coercive field of ultra soft magnetic materials :
- Lajos Karoly VARGA - Zsolt GERCSI - Gy. KOVACS - Frédéric MAZALEYRAT
- J. Magn. Magn. Mater. 301 (2006) pp.527-531
 
High temperature soft magnetic properties of Co-dopped nanocrystalline materials :
- Zsolt GERCSI - Frédéric MAZALEYRAT - Lajos Karoly VARGA
- J. Magn. Magn. Mater. 302 (2006) pp. 454-456
 
Study of magnetoimpedance effect in Co-Fe-Si-B glass-covered microwires :
- S. N. KANE - Francisco ALVES - Zsolt GERCSI - Frédéric MAZALEYRAT - - -
- Sensors and Actuators A 129 (2006) pp. 216-219
 
Microstructure and magnetic properties of Fe85-x Cox Nb5 B8 P2 high temperature nanocrystalline alloys :
- Lajos Karoly VARGA - Gy. KOVACS - Attila KAKAY - Frédéric MAZALEYRAT - Zsolt GERCSI - J. FERENC - E. FAZAKAS - T. KULIK - C. CONDE
- communication ICM 2003, Roma Journal of Magnetism and Magnetic Materials 272-276 (2004) 1506-07
 
Study of structural and magnetic properties of FeCoSiBNbCu alloys :
- Zsolt GERCSI - Shashank KANE - Jean-Marc GRENECHE - Lajos Karoly VARGA - Frédéric MAZALEYRAT
- Présenté à la conférence SCM'04, Seehiem, Allemange Physica Status Solidi(c) 12 (2004) 3603-3607
 
A novel method determining longitudinally induced anisotropy :
- Frédéric MAZALEYRAT - Zsolt GERCSI - Lajos Karoly VARGA
- Journal of Magnetism and Magnetic Materials 280 (2004) 391-394
 
Stress-induced magnetic anisotropy in nanocrystalline alloys :
- Lajos Karoly VARGA - Zsolt GERCSI - Gy. KOVACS - Attila KAKAY - Frédéric MAZALEYRAT
- J. Magn. Magn. Mater., vol 254-255, pp 477-479
 
Induced anisotropy and high temperature behavior of Co-substituted Finemet alloys :
- Frédéric MAZALEYRAT - Zsolt GERCSI - Lajos Karoly VARGA
- Conférence invitée à "PROSIZE", ateliers de l'OTAN, Budmerice, Slovaquie, mai 2003. Publication en cours dans "Properties and applications of nanocrystalline materials from amorphous precursor", P. Svec et M. Miglierini, NATO ARW series, Kluwer
 
Magnetic and structural study of (Fe1-xCox)62 Nb8 B30 bulk amorphous alloys :
- Zsolt GERCSI - Frédéric MAZALEYRAT - S. N. KANE - Lajos Karoly VARGA
- communication RQ11, Oxford 2002 Materials Science and Engineering A375-377 (2004) 1048-52
 
Magnetic properties at elevated temperatures of Co substituted Finemet alloys :
- Frédéric MAZALEYRAT - Zsolt GERCSI - J. FERENC - T. KULIK - Lajos Karoly VARGA
- Communication Oxford 2002, RQ11. Materials Science & Engineering A375-377 (2004) 1110-15