On Tuesday June 25, we have the pleasure to welcome Lindor Diallo from Université de Normandie and INSA Rouen, he will give us a seminar at 14:00, CEA/IRIG, Bat 1005, room 446 entitled :
Atomic scale correlation of structural and magnetic properties of SiC semiconductor implanted with Fe.
The discovery of giant magnetoresistance in 1988 by A. Fert was the starting point for a new discipline in physics: spin electronics or spintronics. The use of a new degree of freedom that is provided by the spin of the electron in addition to its charge has allowed new devices to emerge in the field of transport and information processing and consider lowering energy consumption and improving performance.
Among the materials of spintronics, hopes are placed on diluted magnetic semiconductors (DMS) [1,2,3]. Indeed, the doping of a semiconductor with the 3d transition metals (Cr, Mn, Fe, Co) makes it possible to confer ferromagnetic properties, while keeping the semiconducting nature of the material, giving the possibility of extending the traditional device features and emerging new classes of materials that combine both electrical and magnetic properties in a single device.
With its wide band gap (3.0 eV for 6H-SiC), its excellent transport properties and its great maturity in the microelectronics industry, silicon carbide is a potential material for high temperature, high frequency and high power. Currently, one of the crucial problems in the field of dilute magnetic semiconductors (DMS) is to understand the origin of the magnetic effects observed in these materials.
We propose to use the Atomic Probe Tomography (APT) to map the spatial distribution of Fe atoms within Si (Fe) C. The APT, also known as 3D atomic microscopy, is based on the combination of electric field evaporation, time of flight spectroscopy and detection by a position sensitive detector.
6H-SiC substrates are multi-implanted to achieve a plateau of iron concentration of the order of 2% between 20 and 100 nm. Some samples then undergo rapid thermal annealing after implantation. APT, X-ray diffraction, electron microscopy, SQUID magnetometry and Mössbauer spectroscopy, obtains the structural and magnetic properties. SQUID measurements showed ferromagnetic properties up to ambient with a superparamagnetic contribution.
In this work, the influence of the annealing temperature and the dose of implanted magnetic ions is discussed. The set of results shows us how an APT study correlated with Mössbauer spectroscopy of 57Fe allows a better understanding of the Si (Fe) C system.
(1) T. Dietl, H. ohno, F. Matsuka, J. Cibert, D. ferrand, Science 287 1019 (2000).
(2) J.K. Furdyna, J. Appl. Phys. 64 R29 (1988).
(3) I. Zutic, J. Fabian and S. Das Sarma, Rev. Mod. Phys. 76, 323 (2004)
L. Diallo(1), L. Lechevallier(1), A. Fnidiki(1), M. Viret(3), A. Declémy(4)
(1) Groupe de Physique des Matériaux, Université et INSA de Rouen – UMR CNRS 6634 -Normandie Université, F-76801 St. Etienne du Rouvray, France.
(2) Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), CNRS-IN2P3-Univ. Paris-Sud 11, Bât. 108, 91405 Orsay, France.
(3) Service de Physique de l’Etat Condensé (DSM/IRAMIS/SPEC), UMR 3680 CNRS , Bât. 772, Orme des Merisiers, CEA Saclay 91191 Gif sur Yvette, France.
(4) Institut PPRIME, UPR 3346 CNRS, Université de Poitiers, ENSMA, SP2MI, téléport 2, 11 Bvd M. et P. Curie 86962 Futuroscope, Chasseneuil, France