Desenvolvimento de um microscópio óptico e magnetoóptico de varredura em campo-próximo / Development of a Magneto-optical Scanning Near-field Optical Microscope (MO-SNOM)

AUTOR(ES)

Jeroen Schoenmaker

DATA DE PUBLICAÇÃO

2005

RESUMO

To support nanosciences evolution, there is a strong demand for developing new instrumentation devoted to nano-scale characterization. In this context, the development of the Scanning Near-field Optical Microscope (SNOM) took place. In contrast to traditional optical microscopes, SNOM deals with evanescent electromagnetic radiation and, consequently, the resolution is no longer limited by the Rayleigh criterion. At Laboratório de Materiais Magnéticos (LMM) IFUSP a SNOM devoted to magneto-optical Kerr effect measurements (MO-SNOM) has been developed. The MOSNOM associates the high resolution of the near-field technique to the high sensibility of the magneto-optical Kerr effect. Near-field magneto-optical microscopy is not yet wellestablished and there is a lack of systematic results in the literature. Using the MO-SNOM, amorphous Co70.4Fe4.6Si15B10 particles with 16x16x0.08 microm3 and 4x4x0.08 microm3 dimensions were studied. With resolution better than 200 nm, several magneto-optical differential susceptibility images and local hysteresis loops were obtained. The systematic results uphold the establishment of this new technique. Under the different applied field conditions, the magnetic behavior of the particles was found to be determined by shape anisotropy. Local hysteresis loops presented shapes intrinsic of local field induced process. The unusual hystesesis loops motivated interesting discussion about the conventional magnetic parameters. The MO-SNOM measurements indicate that the near-field transverse magneto-optical Kerr effect is similar to the far-field case. The results are highly supported by far-field magneto-optical microscopy, micromagnetic simulations and magnetic force microscopy measurements. Complementary measurements indicate the MO-SNOM potential to extensive magnetic surface characterization related to pinning potential distribution. Furthermore, measurements on the exchange-bias coupled NiFe/FeMn thin films make evident the MO-SNOM high sensitivity, estimated to be DeltaM ~ 2 x 10-12 emu.

ASSUNTO(S)

magnetic particles microscopia de varredura em campo-próximo near-field microscopy instrumentation for nanotechnology magneto-optical kerr effect efeito magnetoóptico instrumentação para nanotecnologia partículas magnéticas curva de histerese local local characterization magnetic domain wall

Documentos Relacionados

• Simultaneous detection of near-field topographic and fluorescence images of human chromosomes via scanning near-field optical/atomic-force microscopy (SNOAM).
• Inscription of local surface relief gratings with a Scanning Near-field Optical Microscope on an azo-polymer film
• Nanoestruturas metálicas e de silício para intensificação de campo próximo.
• Efeito Kerr magneto-óptico espectral e sperimagnetismo de filmes amorfos de terra rara-Co
• Calcium magneto-optical trap loaded from a decelerated atomic beam