Spin waves excitations in thin film
of expanded austenite phase S(g
N)
1, 2
2
2
2
2
N. Guskos , G. Zolnierkiewicz , P. Berczynski , J. Typek , A. Guskos ,
3
3
J. Baranowska , and S. Fryska
1
Department of Solid State Physics, Faculty of Physics, University of Athens,
Panepistimiopolis, 15 784 Zografou, Athens, Greece
2
Institute of Physics, Faculty of Mechanical Engineering and Mechatronics, West Pomeranian University of Technology,
Al. Piastow 48, 70-311 Szczecin, Poland
3
Institute of Materials Science and Engineering, West Pomeranian University of Technology,
Al. Piastów 17, 70-310 Szczecin, Poland
- When the external field is parallel to the layer surface, only one resonance mode is observed in all samples, which is the uniform mode.
- When the external field is perpendicular to the layer surface, the FMR spectra consist of at least two modes.
- Both odd and even modes are excited with almost equal efficiency what can be explained by inhomogeneous structure of our layers
2
- As the separation of spin waves is proportional to n , the spins of the surface layer should be pinned.
- The diffrences in H for different samples might be caused n
by different saturation magnetization of these samples.
Conclusions
Magnetic resonance spectra were registered on BRUKER E500 X-band (9.4 GHz). The ferromagnetic resonance (FMR) spectra were registered at room temperature using a goniometer enabling sample rotation around vertical axis.
Experimental
0 2000 4000 6000 8000 10000 12000 14000 -400000 -350000 -300000 -250000 -200000 -150000 -100000 -50000 0 50000 100000 150000 200000 250000 300000 350000 90° 80° 70° 60° 50° 40° 30° 20° d c "/ d H [a rb . u n it s ] Magnetic field [G]Sample 1
10° 0 2000 4000 6000 8000 10000 12000 14000 -300000 -250000 -200000 -150000 -100000 -50000 0 50000 100000 150000 200000 250000 300000 350000 400000 90° 80° 70° 60° 50° 40° 30° 20° 10° d c "/ d H [a rb . u n it s ] Magnetic field [G]Sample 2
0° 0 2000 4000 6000 8000 10000 12000 14000 -200000 -150000 -100000 -50000 0 50000 100000 150000 200000 250000 300000 350000 400000 90° 80° 70° 60° 50° 40° 30° 20° 10° d c "/ d H [a rb . u n it s ] Magnetic field [G]Sample 3
0° 0 2000 4000 6000 8000 10000 12000 14000 -250000 -200000 -150000 -100000 -50000 0 50000 100000 150000 200000 250000 300000 90° 80° 70° 60° 50° 40° 30° 20° 10° d c "/ d H [a rb . u n it s ] Magnetic field [G]Sample 4
0° 0 20 40 60 80 100 120 140 160 180 0 2000 4000 6000 8000 10000 12000 14000 R e s o n a n c e fi e ld [G ] Angle [°] Sample 1 Sample 2 Sample 3 Sample 4H
q
Coatings were deposited by reactive sputter deposition at different temperatures and total gas pressures. The deposition chamber was a cylinder with 300 mm diameter and 400 mm high. The magnetron gun with the target was located on the bottom of the chamber. 50 mm diameter target was made of X10CrNi18-10 stainless steel. The target was powdered using a 750 W and 20 kHz pulsed dc supply at a mean target power of 200 W (~0.3 A). Silicon plates used as substrates were ultrasonically degreased, rinsed in alcohol and dried in hot air. Then substrates were placed on a heating holder and biased with RF source (power of 2 W). Coating were deposited for 90 min. Before the deposition, substrates were ion cleaned at pressure 2.66 Pa for 10 min The parameters of the deposition are shown below
.
Samples preparation
Sample designation Temperature Pressure 2 100 oC 0.4 Pa 1 200 oC 0.26 Pa 3 300 oC 0.26 Pa 4 300 oC 0.53 Pah
g
g
w
p
2
4
eff
eff
n
n
k
D
M
H
=
+
-For the external field perpendicular to the layer plane, the resonance field H is given byn
where:
M is the effective magnetizationeff ù is the microwave frequency ã is the gyromagnetic ratio
D is the effective magnon stiffness constanteff
k n is the wave number of the n-th spin wave mode,
h B gm g= L n kn =p 8.5 9.0 9.5 10.0 10.5 11.0 11.5 12.0 12.5 13.0 -80 -60 -40 -20 0 20 40 60 80 100 120 0 2 4 6 8 10 12 14 16 18 9.0 9.5 10.0 10.5 11.0 11.5 12.0 12.5 13.0 d c "/ d H [a rb . u n it s ] Applied field H [kG] 1 2 3 4 n2 H n [k G ] 10.5 11.0 11.5 12.0 12.5 13.0 13.5 14.0 -60 -40 -20 0 20 40 60 0 2 4 6 8 10 12 14 16 18 11.0 11.5 12.0 12.5 13.0 13.5 14.0 d c "/ d H [a rb . u n it s ] Applied field H [kG] 1 2 3 4 H n [k G ] n2
