infm-l’aquila film e multistrati magnetici franco lucari
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INFM-L’AQUILAINFM-L’AQUILA
FILM E MULTISTRATI MAGNETICIFILM E MULTISTRATI MAGNETICI
Franco LucariFranco Lucari
• Film e multistrati magnetici
UNIVERSITÀ DELL’AQUILAUNIVERSITÀ DELL’AQUILA
Università dell’Aquila - FIRBUniversità dell’Aquila - FIRB
Il gruppo è composto da:
• Lucari Franco• D’Orazio Franco• Continenza
AlessandraUtilizza 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 dotazioneLe 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 Apparecchiature a cui è possibile accedere localmenteaccedere localmente
• Diffrazione a raggi X
• SEM (TEM?)
• XPS
• Microscopia a forza atomica
• Microscopia a forza magnetica (?)
Apparecchiature da allestire in Apparecchiature da allestire in parte finanziate da FIRB:parte finanziate da FIRB:
• Sistema d'immagine magnetica Kerr
• Apparecchiatura magneto-ottica in situ sull'apparato di sputtering
• Criostato per Magnetometro AGFM
Materiali studiatiMateriali studiati
• Film e multistrati di:
Fe-Al, Co-Fe, Co-CoO, Ni-NiO
• Ge(Mn)
• CoPt
Magneto-Optical Kerr Effect Magneto-Optical Kerr Effect ((MOKEMOKE)) measurements measurements
variable wavelength,variable wavelength,variable temperature,variable temperature,
Hysteresis loopsHysteresis loops
EXCHANGE-BIAS EXCHANGE-BIAS COUPLING IN Co/CoO COUPLING IN Co/CoO
BILAYERSBILAYERS
sample # substrate O2 Flux (sccm)
d-Co (nm)
d-CoO (nm)
1 glass 1 14.2 4.5 2 glass 2 15.3 4.0 3 glass - 28.0 - 4 Si[100] 1 13.1 4.9
-0.04
-0.02
0.00
0.02
0.04
-6 -4 -2 0 2 4 6
H (kOe)
(°)
200 K
50 K ZFC
50 K FC
Sample #3
0.0
0.5
1.0
1.5
0 100 200T (K)
HE
B (
kOe)
# 1# 2# 3# 4
Exchange-Bias Field vs.
Temperature
Coercive Field vs. Temperature
[Fex/Aly]N multilayers on Si(100)
-0.05
0.00
0.05
-10 -5 0 5 10H (Oe)
K (
°)
Longitudinal MOKE hysteresis on sample [Fe/Al] x 4. The film is oriented with the easy magnetization axis parallel to the H direction
0.0
0.5
1.0
-30 0 30 60 90 120 150 180
(°)
MR/MS
Loop squareness vs. the angle between the [011] axis of the substrate and the magnetic field
direction
[Fex/Aly]4
0
2
4
6
8
10
1 2 3 4 5 6 7N
Hc(O
e)
Coercive field as a function of the number of Fe/Al layer pairs
[Fex/Aly]N
[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 0 2 4 6
H (kOe)
(°
)
Mn 2.7%Mn 4.4%Mn 5.3%
MOKE hysteresis loop at Tmeas = 100 K for the samples deposited at TG = 160 °C.
0
2
4
0 100 200 300T (K)
HC
(kO
e)
Mn 2.7%
Mn4.4%
Mn 5.3% (Hcx10)
Mn 2.7% after aging
Coercive field vs. Temperature
Temperature dependence of the
coercive field for the samples deposited at
TG = 160 °C.
0
0.2
0.4
0.6
0.8
0 100 200 300T (K)
S/x
(°)
Temperature dependence of MOKE
saturation normalized to
Mn concentration for the samples deposited at
TG = 160 °C.
Magnetization vs. Temperature
Mn 2.7%
Mn4.4%
Mn 5.3%
Mn 2.7% after aging
Misure di Magnetizzazione Misure di Magnetizzazione (Alternating Field (Alternating Field MagnetometerMagnetometer))
HysteresisHysteresisandand
Switching Field Switching Field DistributionDistribution
CoPt CoPt T = 600°C, p = 4.7 T = 600°C, p = 4.7 10 10-7-7 mbar mbar
Isothermal Remanent MagnetizationIsothermal Remanent Magnetizationandand
Demagnetization Remanence CurvesDemagnetization Remanence Curves
CoPt CoPt T = 600°C, p = 4.7 T = 600°C, p = 4.7 10 10-7-7 mbar mbar
Magnetization DecayMagnetization Decay
CoPt CoPt T = 600°C, p = 4.7 T = 600°C, p = 4.7 10 10-7-7 mbar mbar
Multiple Segments, Minor Loops, etcMultiple Segments, Minor Loops, etc..
CoPt CoPt T = 500°C, p = 3.6 T = 500°C, p = 3.6 10 10-7-7 mbar mbar
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