The spontaneous resistivity anisotropy in Ni-based alloys
TL;DR: In this paper, the difference in resistivity for currents perpendicular to and parallel to the magnetization direction is due to spin-orbit induced resistivity transfer from the spin down electron current to the spin up electron current.
Abstract: From experiments on a number of Ni based alloys, it is shown that the difference in resistivity for currents perpendicular to and parallel to the magnetization direction is due to spin-orbit induced resistivity transfer from the spin down electron current to the spin up electron current
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TL;DR: In this article, a review of extrinsic magnetotransport effects in ferromagnetic oxides is presented, focusing on grain-boundary, tunnelling and domain-wall magnetoresistance.
Abstract: Magnetic oxides show a variety of extrinsic magnetotransport phenomena: grain-boundary, tunnelling and domain-wall magnetoresistance. In view of these phenomena the role of some magnetic oxides is outstanding: these are believed to be half-metallic having only one spin-subband at the Fermi level. These fully spin-polarized oxides have great potential for applications in spin-electronic devices and have, accordingly, attracted intense research activity in recent years. This review is focused on extrinsic magnetotransport effects in ferromagnetic oxides. It consists of two parts; the second part is devoted to an overview of experimental data and theoretical models for extrinsic magnetotransport phenomena. Here a critical discussion of domain-wall scattering is given. Results on surface and interfacial magnetism in oxides are presented. Spin-polarized tunnelling in ferromagnetic junctions is reviewed and grain-boundary magnetoresistance is interpreted within a model of spin-polarized tunnelling through natural oxide barriers. The situation in ferromagnetic oxides is compared with data and models for conventional ferromagnets. The first part of the review summarizes basic material properties, especially data on the spin polarization and evidence for half-metallicity. Furthermore, intrinsic conduction mechanisms are discussed. An outlook on the further development of oxide spin-electronics concludes this review.
441 citations
Cites methods from "The spontaneous resistivity anisotr..."
...Ziese and Sena (1998) derived an expression for the anisotropic magnetoresistance within a simple atomic state model following the work of Campbell et al (1970) and Malozemoff (1985); this describes the normal AMR component....
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TL;DR: In this paper, a unidirectional magnetoresistance observed in bilayer metal films was used to add directional sensitivity to conventional magnetic sensors based on anisotropic magnetic sensors.
Abstract: A unidirectional magnetoresistance observed in bilayer metal films could be used to add directional sensitivity to conventional magnetic sensors based on anisotropic magnetoresistance.
369 citations
TL;DR: In this article, the properties of magnetic field sensors based on semiconductors such as Hall generators and magnetoresistors, and on magnetic metals such as permalloy and the recently discovered 'giant magnetoresistance' metallic multilayers are discussed.
Abstract: Discusses the properties of magnetic field sensors based on semiconductors such as Hall generators and magnetoresistors, and on magnetic metals, such as permalloy and the recently discovered 'giant magnetoresistance' metallic multilayers. Some emphasis is placed on the comparison between sensors made using these different technologies. Applications of magnetic field sensors in magnetic recording technology and in position sensing are discussed briefly. Typically a sensor has to detect the difference between a high and a low value of field, around an average, which is of the order of 10-3 T in recording applications, but can exceed 0.1 T in position sensors.
229 citations
TL;DR: In this article, the influence of the magnetic and electronic transport properties of the materials on the spin transfer effect in magnetization dynamics is discussed and a modified Landau-Lifshitz-Gilbert equation of motion where the different spin transfer torques are included and discussed their influence on the DW dynamics on the basis of simple 1D models and recent micromagnetic simulations studies.
Abstract: The manipulation of a magnetic domain wall (DW) by a spin polarized current in ferromagnetic nanowires has attracted tremendous interest during the last years due to fundamental questions in the fields of spin dependent transport phenomena and magnetization dynamics but also due to promising applications, such as DW based magnetic memory concepts and logic devices. We comprehensively review recent developments in the field of geometrically confined domain walls and in particular current induced DW dynamics. We focus on the influence of the magnetic and electronic transport properties of the materials on the spin transfer effect in DWs. After considering the different DW structures in ferromagnetic nanowires, the theory of magnetization dynamics induced by a spin polarized current is presented. We first discuss the different current induced torques and their origin in the light of recent theories based on a simple s-d exchange model and beyond. This leads to a modified Landau-Lifshitz-Gilbert equation of motion where the different spin transfer torques are included and we discuss their influence on the DW dynamics on the basis of simple 1D models and recent micromagnetic simulations studies. Experimental results illustrating the effects of spin transfer in different ferromagnetic materials and geometries constitute the body of the review. The case of soft in-plane magnetized nanowires is described first, as it is the most widely studied class of ferromagnetic materials in this field. By direct imaging we show how confined domain walls in nanowires can be displaced using currents in in-plane soft magnetic materials and that using short pulses, fast velocities can be attained. While a spin polarized current can trigger DW depinning or displacement, it can also lead to a modification of the DW structure, which is described in detail as it allows one to deduce information about the underlying spin torque terms. High perpendicular anisotropy materials characterized by narrow domain walls have also raised considerable interest. These materials with only a few nanometer wide DWs combined several key advantages over soft magnetic materials such as higher non-adiabatic effects leading to lower critical current densities and high domain wall velocities. We review recent experimental results obtained in this class of materials and discuss the important implications they entail for the nature of the spin torque effect acting on DWs. (C) 2011 Elsevier B.V. All rights reserved.
180 citations
TL;DR: A large-size single crystal of nearly stoichiometric SrCoO(3) was prepared with a two-step method combining the floating-zone technique and subsequent high oxygen pressure treatment, indicative of the possible effect of orbital fluctuation in the intermediate spin ferromagnetic metallic state.
Abstract: A large-size single crystal of nearly stoichiometric SrCoO(3) was prepared with a two-step method combining the floating-zone technique and subsequent high oxygen pressure treatment. SrCoO(3) crystallizes in a cubic perovskite structure with space group Pm3m, and displays an itinerant ferromagnetic behavior with the Curie temperature of 305 K. The easy magnetization axis is found to be along the [111] direction, and the saturation moment is 2.5 µ(B)/f.u., in accord with the picture of the intermediate spin state. The resistivity at low temperatures (T) is proportional to T(2), indicative of the possible effect of orbital fluctuation in the intermediate spin ferromagnetic metallic state. Unusual anisotropic magnetoresistance is also observed and its possible origin is discussed.
164 citations
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TL;DR: The magnetoresistance of pure Ni and Fe, of Ni-Fe-, Ni-Co, and Ni-Cu-alloys, and of Heusler's alloy has been measured at room temperature and at temperatures of liquid nitrogen and liquid hydrogen as discussed by the authors.
354 citations
TL;DR: In this article, the low-temperature electrical resistivity of dilute nickel-based alloys was measured and it was shown that spin-ensuremath{\uparrow} and spin-ensemblemath{\downarrow} electrons carry current in parallel, providing important implications for the interpretation of transport properties of pure and alloy ferromagnets.
Abstract: Measurements on the low-temperature electrical resistivity of dilute nickel-based alloys give strong evidence that spin-\ensuremath{\uparrow} and spin-\ensuremath{\downarrow} electrons carry current in parallel, providing important implications for the interpretation of transport properties of pure as well as alloy ferromagnets.
262 citations
TL;DR: In this article, the authors show that resistivities of dilute iron based alloys show strong deviations from the Matthiessen's rule, and that these deviations can be explained by a model in which spin ↑ and spin ↓ electrons conduct in parallel.
Abstract: Measurements of resistivities of dilute iron based alloys show strong deviations from. Matthiessen's rule. These deviations can be explained by a model in which spin ↑ and spin ↓ electrons conduct in parallel. The results are consistent with the theory of impurity shielding in these alloys.
113 citations
Posted Content•
TL;DR: In this paper, the authors provided the first experimental demonstration of two current conduction at low temperatures in a ferromagnetic metal, which is consistent with the theory of impurity shielding in these alloys.
Abstract: Measurements of resistivities of dilute iron based alloys show strong deviations from Matthiessen's rule. These deviations can be explained by a model in which spin up and spin down electrons conduct in parallel. The results are consistent with the theory of impurity shielding in these alloys. [This 1967 paper provides the first experimental demonstration of two current conduction at low temperatures in a ferromagnetic metal. One direct consequence of this property is the Giant Magnetoresistance discovered in 1988 by the groups of Albert Fert and of Peter Gr\"unberg].
112 citations