Mode interference and periodic self-focusing of spin waves in permalloy microstripes

We have studied propagation of spin waves in transversally magnetized permalloy microstripes. Our findings show that the interference of spin-wave modes quantized in the direction perpendicular to the stripe axis leads to a spatial pattern characterized by a periodic concentration of the spin-wave energy in the middle of the stripe, which can also be considered as a periodic self-focusing of spin waves. We present a simple model connecting the spatial period of the interference pattern with the width of the stripe and the spin-wave frequency. The studied phenomenon can be used for efficient transmission and processing of microwave-frequency signals by means of spin waves on the nanometer scale.

[1]  B. Hillebrands,et al.  Effective dipolar boundary conditions for dynamic magnetization in thin magnetic stripes , 2002 .

[2]  C. Buehler,et al.  Quantitative analysis of magnetic excitations in Landau flux-closure structures using synchrotron-radiation microscopy. , 2005, Physical review letters.

[3]  R. Hertel,et al.  Domain-wall induced phase shifts in spin waves. , 2004, Physical review letters.

[4]  P. Freitas,et al.  Two-dimensional patterns of spin-wave radiation by rectangular spin-valve elements , 2005 .

[5]  C Fermon,et al.  Spin wave wells in nonellipsoidal micrometer size magnetic elements. , 2002, Physical review letters.

[6]  M. Kostylev,et al.  Spin-wave excitations in finite rectangular elements of Ni 80 Fe 20 , 2005 .

[7]  F. Nizzoli,et al.  Brillouin light scattering investigation of dynamic spin modes confined in cylindrical Permalloy dots , 2003 .

[8]  G. Reiss,et al.  Effect of spin-polarized electric current on spin-wave radiation by spin-valve nanocontacts , 2007 .

[9]  J. P. Park,et al.  Imaging of spin dynamics in closure domain and vortex structures , 2002, cond-mat/0208572.

[10]  C. Fermon,et al.  Microwave spectrum of square Permalloy dots: Quasisaturated state , 2006 .

[11]  S. Chérif,et al.  Experimental and theoretical study of quantized spin-wave modes in micrometer-size permalloy wires , 2001 .

[12]  K. Guslienko,et al.  Strong radiation of spin waves by core reversal of a magnetic vortex and their wave behaviors in magnetic nanowire waveguides. , 2007, Physical review letters.

[13]  A. Slavin,et al.  Dipolar localization of quantized spin-wave modes in thin rectangular magnetic elements , 2003 .

[14]  J. P. Park,et al.  Interactions of spin waves with a magnetic vortex. , 2005, Physical review letters.

[15]  U. Krey,et al.  Fourier transform imaging of spin vortex eigenmodes. , 2004, Physical review letters.

[16]  B. N. Engel,et al.  Phase-locking in double-point-contact spin-transfer devices , 2005, Nature.

[17]  J. Katine,et al.  Electrical measurement of spin-wave interactions of proximate spin transfer nanooscillators. , 2006, Physical review letters.

[18]  F. Giesen,et al.  Spin-wave interference in microscopic rings. , 2006, Physical review letters.

[19]  C. Back,et al.  Spin-wave eigenmodes of permalloy squares with a closure domain structure. , 2005, Physical review letters.

[20]  P. Freitas,et al.  Radiation of spin waves by a single micrometer-sized magnetic element , 2004 .

[21]  Ivanov Ba,et al.  High frequency modes in vortex-state nanomagnets. , 2005 .

[22]  R. Damon,et al.  Magnetostatic modes of a ferromagnet slab , 1961 .

[23]  G. J. Parker,et al.  Time-domain excitation of quantized magnetostatic spin-wave modes in patterned NiFe thin film ensembles , 2003 .

[24]  C. Back,et al.  Spatially resolved dynamic eigenmode spectrum of Co rings. , 2006, Physical review letters.

[25]  J. Katine,et al.  Mutual phase-locking of microwave spin torque nano-oscillators , 2005, Nature.

[26]  C. Chappert,et al.  Lateral quantization of spin waves in micron size magnetic wires , 1998 .

[27]  B. Hillebrands,et al.  Brillouin light scattering studies of confined spin waves: linear and nonlinear confinement , 2001 .

[28]  M. Kostylev,et al.  Dipole-exchange propagating spin-wave modes in metallic ferromagnetic stripes , 2007 .

[29]  G. Leaf,et al.  Normal modes of spin excitations in magnetic nanoparticles , 2004 .

[30]  P. Krzysteczko,et al.  Self-focusing of spin waves in Permalloy microstripes , 2007 .

[31]  C. Chappert,et al.  Brillouin light scattering from quantized spin waves in micron-size magnetic wires , 1999 .