Spectroscopy and Microscopy of Spin-Sensitive Rectification Current Induced by Microwave Radiation

Amplitude-modulated microwave radiation was applied to the junction of a scanning tunneling microscope (STM). Rectification in the tunneling current was induced by the microwave because of the nonlinearity of the junction. It is shown that this rectification current is proportional to the d(2)I/dV(2) signal and exhibits spin-sensitivity. The magnetic domain at the apex of an iron-coated tip was manipulated by applying an external magnetic field. The moment of spin flip and the magnetic hysteresis were measured by changes in the spin-dependent current through the Cr(001) surface.