Current-induced oscillations of a Bloch wall in magnetic thin films

Abstract An electric current traversing a domain wall induces an S-shaped distortion of the wall, in a ferromagnetic film with in-plane magnetization such as NiFe. We calculate the degree of ac wall distortion as a function of current intensity and frequency, for sinusoidal ac drive current. The degree of wall distortion exhibits a maximum for exciting frequencies close to a certain resonance frequency ⋍ 10–100 MHz . We predict the resonance frequency as a function of film thickness. The oscillating wall distortion causes a reduction of the coercive field of the material, also maximum near the resonance frequency. Finally, the complex electrical impedance of a sample containing many parallel walls also exhibits a resonance at that frequency.

[1]  L. Néel,et al.  New Method to Measure Directly the 180° Bloch Wall Energy , 1963 .

[2]  J. Livingston,et al.  Effects of applied currents on domain structures and permeability in amorphous metal ribbons , 1984 .

[3]  N. Smith,et al.  Frequency dependence of the transverse biased permeability in thin permalloy films , 1993 .

[4]  Bertram,et al.  Domain-wall dynamic transitions in thin films. , 1991, Physical review. B, Condensed matter.

[5]  J. Baldwin,et al.  Wall‐Pinning Model of Magnetic Hysteresis , 1969 .

[6]  Berger.  Possible existence of a Josephson effect in ferromagnets. , 1986, Physical review. B, Condensed matter.

[7]  F. Humphrey,et al.  Erratum: Wall oscillations in the presence of in‐plane fields in magnetic bubble materials , 1979 .

[8]  J. Slonczewski,et al.  Magnetic domain walls in bubble materials , 1979 .

[9]  L. Néel.  Remarques sur la théorie des propriétés magnétiques des couches minces et des grains fins , 1956 .

[10]  L. Berger,et al.  Dragging of domains by an electric current in Metglas 2826 MBa) , 1982 .

[11]  C. Aroca,et al.  Measuring the exchange constant Aex in metglas 2826 , 1983 .

[12]  S. Batra,et al.  Field dependence of the flexural domain wall modes , 1987 .

[13]  L. Berger,et al.  Prediction of a domain-drag effect in uniaxial, non-compensated, ferromagnetic metals , 1974 .

[14]  A. E. Labonte,et al.  Two‐Dimensional Bloch‐Type Domain Walls in Ferromagnetic Films , 1969 .

[15]  L. Berger,et al.  Domain‐wall surface energy derived from the complex impedance of Metglas ribbons traversed by ac currents , 1985 .

[16]  E. Jiang,et al.  Domain wall surface energy of metallic glass ribbons by the complex impedance measurement , 1987 .

[17]  M. Kryder,et al.  Magneto-optic studies of wall vibration , 1982 .