We demonstrate current-induced displacement of ferromagnetic domain walls in sub-micrometer fabricated patterns of SrRuO3 films. The displacement, monitored by measuring the extraordinary Hall effect, is induced at zero applied magnetic field and its direction is reversed when the current is reversed. We find that current density in the range of 10 9 − 10 10 A/m 2 is sufficient for domain-wall displacement when the depinning field varies between 50 to 500 Oe. These results indicate relatively high efficiency of the current in displacing domain walls which we believe is related to the narrow width (∼ 3 nm) of domain walls in this compound.PACS numbers: 75.60. Ch, 75.75.+a, 72.25.Ba Occasionally, the functionality of spintronic devices requires the ability to control the magnetic configuration of sub-micrometer magnetic structures. Currently, this goal is achieved in many cases (for instance in novel MRAM devices) by current lines external to the magnetic region that generate Lorentz forces; however, this method suffers from non-locality (due to the weak spatial decay of the magnetic field) and lack of scalability (since the needed current in these lines does not decrease with the magnetic bit size). Consequently, there is an intensive effort to find methods of manipulating the magnetic configuration of such structures by injecting spin-polarized electric current into the target region, a process both local and scalable. In addition to their enormous technological importance, such methods involve fascinating theoretical issues; hence, intensive theoretical and experimental efforts are invested in their study.Two main relevant effects are considered in this respect: (a) the interaction between spin-polarized current injected into a small magnetic region and the magnetic moments of that region, and (b) the interaction between spin polarized current and a ferromagnetic domain wall. The first effect, suggested by Slonzcewski [1], yields magnetic switching while the second effect, suggested by Berger [2], yields domain wall displacement. Here we address the latter effect.Following the theoretical prediction of Berger [2], the interaction of spin-polarized current with a ferromagnetic wall has been studied both theoretically and experimentally. There have been various demonstrations of currentdriven domain wall displacement [4,5,6,7,8,9,10,11] using various methods for detecting the displacement, including magnetic force microscopy [4,7], change in resistance of spin valve structures [5,8], change in longitudinal resistance [6,11], magneto-optics [9, 10] and Hall effect [10]. While current-driven domain wall motion in ferromagnetic semiconductor systems is achieved with moderate current density of less than 10 9 A/m 2 [10], the typical current density for inducing domainwall displacement in metallic systems is in the range of 10 11 − 10 12 A/m 2 . Domain wall displacement at lower currents densities (on the order of 10 10 A/m 2 ) in metal- lic systems is achieved either when the depinning fields are very week (few Oe...

SrRuO3 is a 4d itinerant ferromagnet (Tc ∼150 K) with stripe domain structure. Using highquality thin films of SrRuO3 we study the resistivity induced by its very narrow (∼ 3 nm) Bloch domain walls, ρDW (DWR), at temperatures between 2 K and Tc as a function of the angle, θ, between the electric current and the ferromagnetic domains walls. We find that ρDW (T, θ) = sin 2 θρDW (T, 90) + B(θ)ρDW (T, 0) which provides the first experimental indication that the angular dependence of spin accumulation contribution to DWR is sin 2 θ. We expect magnetic multilayers to exhibit a similar behavior.

In bilayers consisting of ferromagnetic and superconducting films, the ferromagnetic film in its domain state induces inhomogeneous distribution of magnetic fields in the superconducting film. When the ferromagnetic film has bubble magnetic domains in a labyrinth structure, it has been found that the pinning of the vortices increases; hence, the critical current of the superconducting film becomes larger. Here we study the effect of parallel ferromagnetic domain structure in Nb/SrRuO 3 on the critical current of Nb with current flowing perpendicularly to the domains and find that in this case the ferromagnetic domain structure decreases the critical current.

Current pulses injected into a fully magnetized region of the itinerant ferromagnet SrRuO3 destabilize the uniform state and induce the formation of a domain structure when the current density exceeds a certain threshold. We study the temperature and field dependence of the destabilizing current (Ids) and compare the results with the temperature and field dependence exhibited by the current required for depinning domain walls in the same region (Idp). We find a qualitative difference between Ids and Idp and suggest that Ids may be related to current-induced nucleation.

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