Method and device for tunnel microscopy
AssigneeMax-Planck-Gesselschaft zur Forderung Der Wissenschaften E.V.
InventorsJürgen Kirschner, Wulf Wulfhekel
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Abstract
In a method for scanning microscopy, for which the surface of a sample is scanned point-by-point using a tunnel tip and locally resolved tunnel current measurement is performed, during scanning the tunnel tip is remagnetized by a predetermined remagnetization frequency, and from the tunnel current (It) or a z coordinate of the distance between the tunnel tip and the sample or a value derived from this, locally resolved signal components are derived, occurring at the remagnetization frequency and being characteristic for magnetic sample properties, whereby on the basis of the derived signal components an imaging of the magnetic structure of the sample surface is performed.
Claims18
A method for scanning microscopy comprising:
- scanning point-by-point the surface of a sample using a tunnel tip not subject to substantial geometric changes;
- periodically remagnetizing the tunnel tip at a predetermined remagnetization frequency (f) during scanning;
- performing locally resolved measurement of current (It) generated at the tunnel tip;
- deriving locally resolved signal components from the tunnel current (It) or a z coordinate of the distance between the tunnel tip and the sample or a value derived thereof, which occur at the remagnetization frequency (f) and which are characteristic for magnetic sample properties, wherein the signal components measured at local resolution are characteristic for the magnetotunnel resistance between the sample and the tunnel tip and the imaged magnetic structure of the sample surface includes local spin polarization properties of the sample surface;
- and
- imaging the magnetic structure of the sample surface on the basis of signal components derived.
A scanning microscope comprising:
- a tunnel tip which is adapted to be moved across the surface of a sample in an evacuated sample chamber using a piezoelectric drive and at least partially consists of stiff material which at remagnetization is not subject to substantial geometrical changes;
- a control circuit operatively connected to the tunnel tip to control movement of the tunnel tip;
- a display and evaluation system operatively connected to the tunnel tip for display and processing surface characteristics of the sample based on movement of the tunnel tip;
- a magnetizing device for periodic remagnetization of the tunnel tip at a predetermined remagnetization frequency (f) including at least one coil and one oscillator adapted for subjecting the coil with electrical currents changing direction at the magnetization frequency;
- and
- a phase-sensitive amplifier provided for phase-sensitive amplification of the tunnel current (It) or the z coordinate of the tunnel tip or values derived therefrom at the remagnetization frequency (f) or multiples thereof.
Dependencies are inferred from the claim text.