Review of Scientific Instruments vol:76 issue:6 pages:1-5
We describe the design and performance of a detection unit for magnetic resonance force microscopy (MRFM) based on commercially available piezoresistive cantilevers. The magnetic tip attached to the cantilever acts as a field gradient source. The adjustable microstrip-line radio-frequency (rf) circuit, which is placed above the cantilever, enables to use a wide range of frequencies between 2.3 and 4.3 GHz, and to fully benefit from a frequency sweep of the rf magnetic field. The integration of the necessary field gradient source and broadband microstrip-line rf excitation circuit into the MRFM detector allows us to investigate samples of arbitrary size and shape. The integrated system can also be operated as a conventional magnetic force microscope (MFM) detection unit. Performance of our mechanical detector is demonstrated with ferromagnetic resonance and MFM data obtained on CoO/Co exchange biased microstructures. Spatial variations of the MRFM signal, which are induced by a spatially modulated exchange bias, are monitored with a lateral resolution of about 5 mu m. (c) 2005 American Institute of Physics.