Magnetic force microscopy using nonoptical piezoelectric quartz tuning fork detection design with applications to magnetic recording studies

We have developed a novel form of magnetic force microscopy that uses a com mercial piezoelectric quartz tuning fork to detect magnetic forces and forc e gradients. Such a detection system is extremely simple and inexpensive, c ompared to conventional optical methods of cantilever vibration detection. The setup is, in addition, characterized by small size, which makes it attr active for studies done in constrained spaces. The instrument is first desc ribed, then theoretical comparison of signal to noise ratio and resolution is made with the conventional optical detection techniques of cantilever vi bration, and finally, first images of thin film media commercial hard disk magnetic bit transitions, point response of magnetoresistive elements, and field gradients above the write gap of a commercial hard disk head are pres ented. (C) 1998 American Institute of Physics. [S0021-8979(98)28111-4].