4/4 INFM-LAQUILA FILM E MULTISTRATI MAGNETICI Franco Lucari INFM-LAQUILA FILM E MULTISTRATI...

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

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Page 1: 4/4 INFM-LAQUILA FILM E MULTISTRATI MAGNETICI Franco Lucari INFM-LAQUILA FILM E MULTISTRATI MAGNETICI Franco Lucari.

4/44/4

INFM-L’AQUILAINFM-L’AQUILA    

FILM E MULTISTRATI MAGNETICIFILM E MULTISTRATI MAGNETICI    

Franco LucariFranco Lucari  

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• Film e multistrati magnetici

UNIVERSITÀ DELL’AQUILAUNIVERSITÀ DELL’AQUILA

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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

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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

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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 (?)

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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

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Materiali studiatiMateriali studiati

• Film e multistrati di:

Fe-Al, Co-Fe, Co-CoO, Ni-NiO

• Ge(Mn)

• CoPt

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Magneto-Optical Kerr Effect Magneto-Optical Kerr Effect ((MOKEMOKE)) measurements measurements

variable wavelength,variable wavelength,variable temperature,variable temperature,

Hysteresis loopsHysteresis loops

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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

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-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

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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

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[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

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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

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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

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[CoFe]

T = 30 K - Minor Loops

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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.

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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.

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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

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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

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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

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Magnetization DecayMagnetization Decay

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

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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