Circular dots of permalloy with appropriate aspect ratio can exhibit a vortex structure with perpendicular magnetization at the core [1,2]. In this paper, the dynamic properties of some dots with the above mentioned characteristics, have been sistematically investigated by Brillouin light scattering (BLS) from thermally excited spin waves. Fig.1 shows the comparison between the BLS spectrum of the continuous permalloy film and that of circular dots with diameter of 0.2 micron, recorded in the same experimental conditions. These spectra give evidence of a marked discretization of the spin wave spectrum in agreement with the theoretical prediction of Guslienko et al. [3]. In fact, instead of the peak associated to Damon-Eshbach mode measured for the continuous film, five well resolved peaks are present on both sides of the spectrum of the patterned sample. The dependence of the frequency of these discrete modes on both the intensity of the external applied field and the in-plane wavector has been measured. The experimental frequencies have been compared to those calculated according to the model proposed in Ref.3. We show that in the wavevector interval investigated, the frequency of these discrete modes is dispersionless and the frequency monotonously increases with the intensity of the magnetic field. Similar results were observed by Jorzick et al. in circular permalloy dots with diameter of 1 and 2 micron.[4] REFERENCES [1] T. Shinjo, T. Okuno, R. Hassdorf, K. Shigeto, and T. Ono, Science 289, 930 (2000) [2] T. Okuno, K. Shigeto, T. Ono, K. Mibu, and T. Shinjo, Proceeding of the MML01 Conference. [3] K. Yu Guslienko and A. N. Slavin, J. Magn. Magn. Mater. 215, 576 (2000). [4] J. Jorzick, S. O. Demokritov, B. Hillebrands, B. Bartenlian, C. Chappert, D. Decanini, F. Rousseaux, and E. Cambril, Appl. Phys. Lett. 75, 3859, (1999). --Presentazione poster by R. Zivieri - Conferenza internazionale
Dynamic properties of submicron circular permalloy dots -- Presentazione poster by R. Zivieri - Conferenza internazionale
ZIVIERI, Roberto;NIZZOLI, Fabrizio;
2002
Abstract
Circular dots of permalloy with appropriate aspect ratio can exhibit a vortex structure with perpendicular magnetization at the core [1,2]. In this paper, the dynamic properties of some dots with the above mentioned characteristics, have been sistematically investigated by Brillouin light scattering (BLS) from thermally excited spin waves. Fig.1 shows the comparison between the BLS spectrum of the continuous permalloy film and that of circular dots with diameter of 0.2 micron, recorded in the same experimental conditions. These spectra give evidence of a marked discretization of the spin wave spectrum in agreement with the theoretical prediction of Guslienko et al. [3]. In fact, instead of the peak associated to Damon-Eshbach mode measured for the continuous film, five well resolved peaks are present on both sides of the spectrum of the patterned sample. The dependence of the frequency of these discrete modes on both the intensity of the external applied field and the in-plane wavector has been measured. The experimental frequencies have been compared to those calculated according to the model proposed in Ref.3. We show that in the wavevector interval investigated, the frequency of these discrete modes is dispersionless and the frequency monotonously increases with the intensity of the magnetic field. Similar results were observed by Jorzick et al. in circular permalloy dots with diameter of 1 and 2 micron.[4] REFERENCES [1] T. Shinjo, T. Okuno, R. Hassdorf, K. Shigeto, and T. Ono, Science 289, 930 (2000) [2] T. Okuno, K. Shigeto, T. Ono, K. Mibu, and T. Shinjo, Proceeding of the MML01 Conference. [3] K. Yu Guslienko and A. N. Slavin, J. Magn. Magn. Mater. 215, 576 (2000). [4] J. Jorzick, S. O. Demokritov, B. Hillebrands, B. Bartenlian, C. Chappert, D. Decanini, F. Rousseaux, and E. Cambril, Appl. Phys. Lett. 75, 3859, (1999). --Presentazione poster by R. Zivieri - Conferenza internazionaleI documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
