Scanning Magnetoresistive Microscope

Scanning Magnetoresistive Microscopy (SMRM)

We have developed a Magnetic Microscope with a MR sensor as the sensing element. It offers submicron resolution and can image current carrying devices like ICs and other solid state devices. It has also been successfully used to image magnetic particles and patterned structures which can rival the resolution of conventional imaging devices like MFM.

Here are some SMRM images and movies.

1) Co-rings

A sequence of SMRM images of 4 micron Co rings, measured in the absence of field, for as-deposited samples after exposure to differing magnetic field values: (a) 1000 Oe, (b) -500 Oe, (c) -250 Oe. Bottom row is the corresponding images of individual ring. The image contrast in (a) and (b) is normalized to same field scale (+/- 80 Oe), whereas the contrast in (c) is normalized to (+/-10 Oe). The arrow on the right shows the applied field direction (positive) before each scan.

2) NiFe(Permalloy) Dots

5 micron Permaolly square dots at remanence. The different intermediate states are seen clearly. Magnetization configurations of a single-vortex FC state(A), Diamond state(B) and Shifted FC state(C) are shown schematically.

SMRM images of a single square in a single-vortex state. The CW (a) and CCW (b) magnetization orientation in the two images are distinguished by the opposing dark-bright contrast

3) Movies

1) Magnetic Reversal of 5 micron square Permalloy dots

2) Co-rings switching

3) CrO2 dots switching

4) Images of Current Carrying devices

SMRM images of a Al-NiFe junction when a current of 190 microAmps is passed through 2 micron thick Al- NiFe wires.


Please send your comments and thoughts to
Professor Gang Xiao