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magnetic materials

preparation of magnetic SmFe films by pulsed laser deposition at 157 nm


Preparation and characterization of magnetic thin films based on rare earth-transition metals by applying advanced state of the art Pulse Laser Deposition techniques <http://www.eie.gr/eie-english.htm>.

Thin films were fabricated by PLD at 157 nm from Sm13.7Fe86.3 targets on Si substrates coated with Ta (Fig.1) at 1 atm He background pressure at 25 mJ per pulse. The dimensions of the nanocrystals were between 10-500 nm (Fig. 2). At 157 nm, the Fe/rare earth ratio for the film remains the same as it is in the initial target. On the contrary, at 248 nm the ratio Fe/rare earth on the film, is higher than on the target. Under the same experimental conditions at high vacuum (10-5 mbar), only amorphous film 1-2 nm thick (Fig. 3) together with ablated droplets of different size were deposited on Ta/Si substrates.
 


Figure 1. AFM picture of Ta film deposited by sputtering on Si substra
te (courtesy
Dr. Evangelia Sarantopoulou)
 


Figure 2. SEM image of the Sm-Fe
nanocrystals obtained in the
He background pressure.
 


Figure 3. Dark-field TEM micrograph of
cross-section of Sm-Fe thin film on a Ta/Si substrate deposited by PLD at 157 nm.
Ta and Sm-Fe layers are amorphous
(inset is SAED pattern of both layers).


Figure 4. STEM/HAADF image of the PLD deposited Sm-Fe-Ta-N (droplet with nano-crystallites) obtained in N2 background
pressure before annealing and nitriding.

 

comments & suggestions to:  sanja fidler