Onde di spin in film epitassiali ultrasottili

ed in campioni patterned

FIRBParma, 10 ott. 2003

G. Carlotti, G. Gubbiotti, M. Madami, G. Socino, S. Tacchi

Laboratorio GHOST - Unità INFM di Perugia

Brillouin Light Scattering

LASER

CONTROL UNIT

DATAACQUISITION

-40 -30 -20 -10 0 10 20 30 40

Frequency Shift (GHz)

beam-splitter

SAMPLE

polariser

FABRY-PEROT TANDEM 3+3 PASS INTERFEROMETER

FP1

P.D.

FP2

FIRBParma, 10 ott. 2003

La camera di ultra alto vuoto

FIRBParma, 10 ott. 2003

Fe/GaAs(001) e Co/GaAs(001)

5.654 Å

Fe bcc (001)

2.87 Å

Co bcc (001)

2.82 Å

FIRBParma, 10 ott. 2003

[110]

[110]

100 Å30 Å

4 Å

Fe/GaAs(100) : Analisi strutturale tramite LEED

I film vengono depositati direttamente sulla superficie

ricostruita (4x6) del GaAs(100)

Si evidenzia una buonaepitassia fino agli spessori

più elevati

FIRBParma, 10 ott. 2003

0 1 2 3 4 50

5

10

15

20

25

30

35

[100]

50 Å

6 Å

10 Å15 Å30 Å100 Å

Freq

uenz

a (G

Hz)

Campo applicato (kOe)0 1 2 3 4

10

15

20

25

30

[110]

50 Å

100 Å

Freq

uenz

a (G

Hz)

Campo applicato (kOe)

Spettroscopia di luce Brillouin : studio delle proprietà magnetiche

FIRBParma, 10 ott. 2003

-90 -45 0 45 90 135 1802

4

6

8

10

12

14

16

18

20100 Å

50 Å

30 Å

15 Å

10 Å

6 Å

4 ÅH= 1 kOe

[110][010][110][100][110]Fr

eque

nza

(GH

z)

angolo in piano (°)

Studio dell’anisotropia nel piano

FIRBParma, 10 ott. 2003

dnominale

(Å)

d(Å)

4MS

(kOe)

4Meff

(kOe)

K2 (105)

(105erg/cm3)

K4(105)

(105erg/cm3)

Ks(105)(105erg/cm3)

100 93±5 21 20.8±0.1 0.4±0.1 3.2±0.1 1.8±0.8

50 48±3 21 20.8±0.1 1.3±0.3 2.8±0.1 2.0±0.9

30 27±2 20 18.5±0.4 1.8±0.2 2.1±0.2 12±3

15 13±2 19 14.0±0.8 2.9±0.3 1.1±0.3 38±6

10 10 19 8.7±1.3 4.8±0.6 1.8±0.3 78±10

6 6 17 3±2 6.9±0.6 -0.8±0.2 94±12

4 4 17 0±2 9.2±0.4 -13.2±1.6 116±14

Analisi quantitativa

FIRBParma, 10 ott. 2003

-45 0 45 90 135

12

14

16

30 Å

-45 0 45 90 1358

10

12

14

15 Å

-45 0 45 90 135

8

10

12

10 Å

-45 0 45 90 135

2

4

6

8

10

6 Å

non ricoperto ricoperto 1 ML Cu

angolo in piano (°)

Fre

que

nza

(G

Hz)

Effetto del ricoprimento sulla anisotropia nel piano

FIRBParma, 10 ott. 2003

Dot circolari di Permalloy (Ni81Fe19) con struttura a vortice

-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5-1.0

-0.5

0.0

0.5

1.0

R=0.1 m

Y A

xis

Titl

e

H (kOe)

-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5

0

R=0.4 m

R=0.5 m

-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5

R=0.3 m

0

Continuous film

-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5

0

R=0.2 m

H (kOe)

-1.0

-0.5

0.0

0.5

1.0

FIRBParma, 10 ott. 2003

-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5

-1.0

-0.5

0.0

0.5

1.0

H

Nor

mal

ized

Ker

r sig

nal

H (Oe)-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5

-1.0

-0.5

0.0

0.5

1.0

H

Nor

mal

ized

Ker

r sig

nal

H (Oe)-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5

-1.0

-0.5

0.0

0.5

1.0

H

Nor

mal

ized

Ker

r sig

nal

H (Oe)-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5

-1.0

-0.5

0.0

0.5

1.0

H

Nor

mal

ized

Ker

r sig

nal

H (Oe)-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5

-1.0

-0.5

0.0

0.5

1.0

H

Nor

mal

ized

Ker

r sig

nal

H (Oe)-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5

-1.0

-0.5

0.0

0.5

1.0

H

Nor

mal

ized

Ker

r sig

nal

H (Oe)-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5

-1.0

-0.5

0.0

0.5

1.0

H

Nor

mal

ized

Ker

r sig

nal

H (Oe)-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5

-1.0

-0.5

0.0

0.5

1.0

H

Nor

mal

ized

Ker

r sig

nal

H (Oe)-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5

-1.0

-0.5

0.0

0.5

1.0

H

Nor

mal

ized

Ker

r sig

nal

H (Oe)

FIRBParma, 10 ott. 2003

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.54

8

12

16

20

In-plane wavevector q ||(105cm-1)

m=0, n=10

m=0, n=3

m=1, n=3m=1, n=2

m=1, n=1 &m=0, n=2

m=0, n=1

R=500 nm

Spi

n-w

ave

frequ

ency

(GH

z)

In-plane wavevector q ||(105cm-1)

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.54

8

12

16

20

D3

D2

D1

B3

B2

B1

LM

m=0, n=2

R = 100 nm

m=0, n=4

m=1, n=1

}Backwards n=1,2

m=1, n=3

m=0, n=3m=1, n=2

m=0, n=1

Spi

n-w

ave

frequ

ency

(GH

z)

In-plane wavevector q ||(105cm-1)

0.0 0.5 1.0 1.5 2.0 2.5 3.04

6

8

10

12

14

16

18

20

22

m=0, n=8

}

R = 300 nm

m=1, n=3

m=1, n=2m=0, n=3-7

m=1, n=1; m=0, n=2m=0, n=1

Spi

n-w

ave

frequ

ency

(GH

z)

In-plane wavevector q||(105cm-1)

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.54

8

12

16

20

m=0, n=7

m=0, n=9

R =400 nm

m=1, n=3

m=1, n=2

m=1, n=1 & m=0, n=2

m=0, n=1

Spin

-wav

e fr

eque

ncy

(GH

z)

In-plane wavevector q ||(105cm-1)

0.0 0.5 1.0 1.5 2.0 2.5 3.04

8

12

16

20Continuous film

Spi

n-w

ave

frequ

ency

(GH

z)

0.0 0.5 1.0 1.5 2.0 2.5 3.04

8

12

16

20

Backward n=3

LM

m=0, n=2

} m=0,n=3-5m=1,n=1

Backward n=1Backward n=2

R = 200 nm

m=1,n=3 &m=0, n=6m=1,n=2

m=0, n=1

Spi

n-w

ave

frequ

ency

(GH

z)

In-plane wavevector q ||(105cm-1)

FIRBParma, 10 ott. 2003

-25 -20 -15 -10 -5 0 5 10 15 20 25

DE PSSW

LMD

3

D1

D2

B1B2

B3

R=400 nm

R=500 nm

R=300 nm

R=200 nm

R=100 nm

PY film

Inte

nsity

(a.u

.)

Frequency shift (GHz)

-25-20 -15 -10 -5 0 5 10 15 20 25

R=100 nm

3.0 kOe

2.0 kOe

2.5 kOe

1.5 kOe

1.0 kOe

Inte

nsity

(a.u

.)

Frequency shift (GHz)

1.0 1.5 2.0 2.50

5

10

15

20

m=1, n=2

m=0, n=2}

Backward n=1

R = 200 nmm=1, n=3 &m=0, n=6

m=0, n=3-5m=1, n=1

m=0, n=1

LM

H (kOe)

Spi

n-w

ave

Freq

uenc

y (G

Hz)

1.0 1.5 2.0 2.5 3.0 3.5 4.00

5

10

15

20 R = 100 nm

inc = 10o

LM

Backwardsn=1 & n=2

}

m=0, n=4m=1, n=3

m=0, n=2

m=1, n=2m=0, n=3m=1, n=1

m=0, n=1

Spi

n-w

ave

Freq

uenc

y (G

Hz)

H (kOe)1.01.52.02.53.03.54.0

0

4

8

12

16

20m=0, n=7

m=0, n=8

} m=0, n=3-6

R = 300 nmm=1, n=3 &

m=0, n=2

m=1, n=2 &

m=1, n=1

m=0, n=1

Spi

n-w

ave

Freq

uenc

y (G

Hz)

H (kOe)

1.0 1.5 2.0 2.50

5

10

15

20 Continuous film

m=0, n=3-5}

m=1, n=1

m=1, n=2

m=0, n=2

m=1, n=3

m=0, n=1

R = 500 nm

Spi

n-w

ave

Freq

uenc

y (G

Hz)

H (kOe)1.01.5 2.02.53.0 3.5 4.00

5

10

15

20m=0, n=3-5}

m=0, n=2

m=1, n=3m=1, n=2

m=1, n=1

m=0, n=1

R = 400 nmS

pin-

wav

e fre

quen

cy (G

Hz)

H (kOe)

0.51.01.52.02.53.03.50

4

8

12

16

20

24

Spi

n-w

ave

Freq

uenc

y (G

Hz)

H (kOe)

FIRBParma, 10 ott. 2003

FIRBParma, 10 ott. 2003

In the future, we plan to:

produce patterned elements starting from the above mentioned Fe and Co epitaxial films on GaAs, in order to study the interplay between the intrinsic anisotropy and that induced by the shape of the elements. The conditions to obtain the single-domain magnetic state will be analysed.

optimize the performance of the AFM-MFM microscope.

achieve a clear comprehension of the physical characteristics of the discretized modes revealed in Brillouin spectra (distribution of the dynamical field amplitude) in nanometric magnetic elements with different shape and separation.