Tubular nanosized magnetic wires with 360° magnetic domain wallu

Abstract

The present invention is directed towards a tubular nanosized magnetic wire, wherein the nanosized magnetic wire comprises: a tubular magnetic shell surrounding a longitudinal axis of the wire, at least one region of the tubular magnetic shell is capable of providing a 360° magnetic domain wall, wherein the 360° magnetic domain wall is self-stabilizing and has a magnetization going from a parallel alignment to a perpendicular alignment and to a parallel alignment with regards to the wire axis. The present invention also provides a practical method capable of making a tubular nanosized magnetic wire with a self-stabilizing, 360° magnetic domain wall. The present invention also relates to the use of the tubular nanosized magnetic wire in a racetrack memory device.

Description

FIELD OF THE INVENTION[0001]The invention relates to the field of tubular nanosized magnetic wire and in particular to a tubular nanosized magnetic wire comprising a tubular magnetic shell surrounding a longitudinal axis of the wire, wherein at least one region of the tubular magnetic shell is capable of providing a 360° magnetic domain wall. The invention also relates to a racetrack memory device making use of tubular nanosized magnetic wires with 360° magnetic domain walls.BACKGROUND OF THE INVENTION[0002]Magnetic materials have been used in functional devices for decades, such as recording devices including hard disk drives (HDDs), magnetoresistive random-access memory (MRAM), bubble and thin-film data storage, sensor and domain shift register devices. Most of these traditional functional devices are based on the control of magnetic domains. For example, recording media use single magnetic domain states with two opposite magnetization directions to represent the information bits ...

AI Technical Summary

Benefits of technology

[0008]The tubular geometry of the nanosized magnetic wire allows for 360° domain walls (i.e. domainwalls in which the local magnetic polarization undergoes a 360° rotation when traversing from one domain to another) to be self stabilizing (i.e. topologically stabilized) as the domain walls loop around the tube and in on themselves.

[0020]In a preferred embodiment the step of producing the tubular nanosized magnetic wire comprises the step of: producing the tubular nanosized magnetic wire by standard electron beam lithography and mask techniques with successive sputtering steps. In another aspect of the invention the tubular nanosized magnetic wire is used in a racetrack memory device. Racetrack memory devices are gaining interest as high-density storage devices. The use of tubular nanosized magnetic wires according to the invention is advantageously due to their stability.

Problems solved by technology

Indeed, propagation of domain walls in planar nanowires is ultimately limited by Walker breakdown, which describes a process whereby an anti-vortex structure is periodically nucleated and annihilated at the wire edges, causing the motion of the domain wall to become non-uniform.

The resulting technical problem is the instability and slow speed of magnetic domain walls.

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