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Title: Magnetometry of micro-magnets with electrostatically defined Hall bars

Micro-magnets are key components for quantum information processing with individual spins, enabling arbitrary rotations and addressability. In this work, characterization of sub-micrometer sized CoFe ferromagnets is performed with Hall bars electrostatically defined in a two-dimensional electron gas. Due to the ballistic nature of electron transport in the cross junction of the Hall bar, anomalies such as the quenched Hall effect appear near zero external magnetic field, thus hindering the sensitivity of the magnetometer to small magnetic fields. However, it is shown that the sensitivity of the diffusive limit can be almost completely restored at low temperatures using a large current density in the Hall bar of about 10 A/m. Overcoming the size limitation of conventional etched Hall bars with electrostatic gating enables the measurement of magnetization curves of 440 nm wide micro-magnets with a signal-to-noise ratio above 10{sup 3}. Furthermore, the inhomogeneity of the stray magnetic field created by the micro-magnets is directly measured using the gate-voltage-dependent width of the sensitive area of the Hall bar.
Authors:
; ; ;  [1] ;  [1] ;  [2]
  1. Département de Physique, Université de Sherbrooke, J1K 2R1 Sherbrooke, Québec (Canada)
  2. (CIFAR), M5G 1Z8 Toronto, Ontario (Canada)
Publication Date:
OSTI Identifier:
22486163
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 22; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CURRENT DENSITY; ELECTRIC POTENTIAL; ELECTRON GAS; HALL EFFECT; MAGNETIC FIELDS; MAGNETIZATION; MAGNETS; QUANTUM INFORMATION; SENSITIVITY; SIGNAL-TO-NOISE RATIO; SPIN; TWO-DIMENSIONAL SYSTEMS