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Title: Detection of ferromagnetic domain wall pinning and depinning with a semiconductor device

We demonstrate the detection of a ferromagnetic domain wall using a nanoscale Hall cross. A narrow permalloy wire is defined lithographically on top of a Hall cross fabricated from an InAs quantum well. The width of the Hall cross (500 nm–1 μm) is similar to the width of the ferromagnetic wire (200–500 nm), and a geometric pinning site is fabricated in the ferromagnetic wire to trap a domain wall within the area of the Hall cross. The devices provide a signal that is often the same order of magnitude as the offset Hall voltage when a domain wall is located above the Hall cross, and may be useful for memory applications. Different geometries for the Hall cross and ferromagnetic wire are tested, and radiofrequency pulses are sent into the wire to demonstrate current driven domain wall motion. Further changes to the Hall bar geometry with respect to the wire geometry are investigated by numerical computation. A large gain in signal is seen for Hall bars only slightly wider than the ferromagnetic wires as compared to those twice as wide, as well as a larger sensitivity to the exact position of the domain wall with respect to the center of the Hall cross.
Authors:
; ;  [1]
  1. Naval Research Laboratory, Washington, D.C. 20375 (United States)
Publication Date:
OSTI Identifier:
22493064
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 23; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CALCULATION METHODS; ELECTRIC POTENTIAL; FERROMAGNETISM; GEOMETRY; HALL EFFECT; INDIUM ARSENIDES; MAGNETIC FLUX; PERMALLOY; PULSES; QUANTUM WELLS; RADIOWAVE RADIATION; SEMICONDUCTOR DEVICES; SENSITIVITY; SIGNALS; WIRES