INFM-L’AQUILA FILM E MULTISTRATI MAGNETICI Franco Lucari 4/4

UNIVERSITÀ DELL’AQUILA Film e multistrati magnetici

Università dell’Aquila - FIRB Il gruppo è composto da: Lucari Franco D’Orazio Franco Continenza Alessandra Utilizza alcuni borsisti oltre a due tecnici: Giammaria Franco Rossi Lorella Tematiche di interesse: N. 1 e N. 4 Work packages: WP1, WP3 e WP4

Le apparecchiature in dotazione Apparato di misura magneto-ottico per misure Faraday, Kerr polare o longitudinale, MCD, MLD: campo magnetico B≤5600 gauss, temperatura 4 ≤T≤300 K, lunghezza d'onda 0.4≤l≤2.6 mm. Suscettometro Lakeshore 7030: frequenza 5≤n≤10000 Hz, temperatura 15 ≤T≤300 K, campo magnetico di misura 0.1≤H≤25 Oe. Apparato di deposizione per sputtering (magnetron, 3 catodi) Magnetometro AGFM Princeton Instr., Campo B < 1.4 T Calcolatori

Apparecchiature a cui è possibile accedere localmente Diffrazione a raggi X SEM (TEM?) XPS Microscopia a forza atomica Microscopia a forza magnetica (?)

Apparecchiature da allestire in parte finanziate da FIRB: Sistema d'immagine magnetica Kerr Apparecchiatura magneto-ottica in situ sull'apparato di sputtering Criostato per Magnetometro AGFM

Fe-Al, Co-Fe, Co-CoO, Ni-NiO Materiali studiati Film e multistrati di: Fe-Al, Co-Fe, Co-CoO, Ni-NiO Ge(Mn) CoPt

Magneto-Optical Kerr Effect (MOKE) measurements variable wavelength, variable temperature, Hysteresis loops

EXCHANGE-BIAS COUPLING IN Co/CoO BILAYERS

Sample #3

Exchange-Bias Field vs. Temperature Coercive Field vs. Temperature

[Fex/Aly]N multilayers on Si(100) Longitudinal MOKE hysteresis on sample [Fe/Al] x 4. The film is oriented with the easy magnetization axis parallel to the H direction

[Fex/Aly]4 Loop squareness vs. the angle between the [011] axis of the substrate and the magnetic field direction

Coercive field as a function of the number of Fe/Al layer pairs [Fex/Aly]N Coercive field as a function of the number of Fe/Al layer pairs

[CoFe] T = 30 K - Minor Loops

MnxGe1-x -0.03 -0.02 -0.01 0.00 0.01 0.02 0.03 -6 -4 -2 2 4 6 H (kOe) q (°) Mn 2.7% Mn 4.4% Mn 5.3% MOKE hysteresis loop at T meas = 100 K for the samples deposited at T G = 160 °C.

Coercive field vs. Temperature 4 Temperature dependence of the (kOe) coercive field for the C samples deposited at H T = 160 °C. Mn 2.7% G 2 Mn4.4% Mn 5.3% (Hcx10) Mn 2.7% after aging 100 200 300 T (K)

Magnetization vs. Temperature 0.8 Temperature dependence of MOKE saturation normalized to 0.6 Mn concentration for the samples deposited at /x (°) T = 160 °C. S G Mn 2.7% 0.4 Mn4.4% Mn 5.3% Mn 2.7% after aging 0.2 100 200 300 T (K)

Misure di Magnetizzazione (Alternating Field Magnetometer) Hysteresis and Switching Field Distribution CoPt T = 600°C, p = 4.7  10-7 mbar

Isothermal Remanent Magnetization and Demagnetization Remanence Curves CoPt T = 600°C, p = 4.7  10-7 mbar

Magnetization Decay CoPt T = 600°C, p = 4.7  10-7 mbar

Multiple Segments, Minor Loops, etc. CoPt T = 500°C, p = 3.6  10-7 mbar