Integration of scanning near field polarization optical microscopy and atomic force microscopy for investigation of magnetic and ferroelectric materials

Abstract

We demonstrate application of integration scanning near-field optical microscopy and atomic force microscopy for investigation of magnetic and ferroelectric materials. This integration is made by using innovative optical and micromechanical components. Optical measuring head with cantilever holder was designed for both near-field optical microscopy and atomic force microscopy modes. Hollow pyramid cantilever with aperture at the tip was designed for registration both optical signal and tip=sample interaction forces. Cantilever aperture was made by ion beam at the center of pyramid. Same probe was used for both topography and domain structure visualization of magnetic samples. Bi: YIG-thin films topography and domain structure were investigated by this method as well as by conventional magnetic force microscopy (MFM). In integrated method of scanning nearfield polarization optical microscopy and atomic force microscopy samples were excited through cantilever aperture by tightly focused linearly polarized laser beam. Magneto-optical effect of the rotation of polarization plane of transmitted light depends on domain orientation. Visualization of magnetic domains was performed by detecting cross polarized component of transmitted light. Near field map of magnetic domains provides direct information of the magnetic moment of domains unlike MFM image which provides distribution of magnetic force gradient. Moreover, non-magnetic hollow-pyramid probe prevents sample from possible disturbances by internal magnetic moment of the MFM probe. Comparison of results obtained by near field polarization microscopy and conventional MFM was performed. We demonstrate possibility of investigation of topography and domain structure ferroelectric materials by integration method of near-field optical microscopy and atomic force microscopy.