Magnetic AFM imaging using an uncoated silicon-nitride cantilever: A sensitive new approach for mapping magnetic nanomaterials at the nanoscale

ANYL 178

Jayne C. Garno, jgarno@lsu.edu, Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton Rouge, LA 70803 and Song Xu, Nanotechnology Measurements Division, Agilent Technologies, Chandler, AZ 85282.
Magnetic nanomaterials can be mapped at sizes below 200 nm by combining contact-mode AFM imaging with sample modulation. The flux of an AC-generated electromagnetic field is used to selectively induce physical movement of magnetic nanomaterials and this movement can be detected using a non-magnetic AFM cantilever operated in contact-mode. A non-magnetic AFM tip is brought into contact with the sample surface using constant force feedback. The motion of magnetic nanomaterials on surfaces is sensed by the tip when it touches the vibrating domains during scans. Only the magnetic domains vibrate, providing selective contrast. A lock-in amplifier is used to acquire the amplitude and phase components of the AC signal which provides extreme sensitivity for changes in AFM tip movement. Responses for both the amplitude/phase changes are simultaneously mapped with the topographic channel, and spectra of the vibrational response are acquired with nanoscale resolution using magnetic sample modulation or MSM.
 

Directed Assemblies Using Surface Templates
8:25 AM-12:05 PM, Wednesday, April 9, 2008 Morial Convention Center -- Rm. 335, Oral

Division of Analytical Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008