4:00 PM - 6:00 PM
[5p-PB5-3] Sensitive observations of magnetic domains using optical filters with Au nanogaps
Keywords:observation of magnetic domains, magneto-optical Kerr effect, Electric field enhancement
We developed the observation technique of magnetic domains in Nd-Fe-B magnetic materials using a magneto-optical Kerr effect and plasmon resonances induced by optical filters which consist of Au nanogaps. Observation of the magnetic domains has renewed attention in recent years to investigate the magnetic properties of the materials which depend on the magnetic microstructures. One of the magnetic domain observation methods is a magneto-optical Kerr microscopy, which has an advantage that the magnetic domains can be dynamically observed under magnetic fields. On the other hand, the sensitivity of the microscopies depends on the Kerr rotation angle of the magnetic materials.
In this study, we proposed the combined technique to improve the sensitivity of the observation of the magnetic domains using the magneto-optical Kerr effect and plasmon resonances. The plasmon resonances were induced by using optical filters which consist of Au nanogaps. The nanogaps were formed by self-organization of Au nanoparticles. Au thin films were deposited on glass substrates, following that the samples were heated at 350°C on a hot plate in air. The optical filters were put on the surface of the Nd-Fe-B magnetic materials. Then, the images were observed using a magneto-optical Kerr microscopy. Obtained images reveal that the contrast ratio of the area without and with the optical filters changed from 55:96 to 49: 109. The contrast was improved by using the optical filters. It was also confirmed that the observation of the magnetic domains is possible under external magnetic fields.
In this study, we proposed the combined technique to improve the sensitivity of the observation of the magnetic domains using the magneto-optical Kerr effect and plasmon resonances. The plasmon resonances were induced by using optical filters which consist of Au nanogaps. The nanogaps were formed by self-organization of Au nanoparticles. Au thin films were deposited on glass substrates, following that the samples were heated at 350°C on a hot plate in air. The optical filters were put on the surface of the Nd-Fe-B magnetic materials. Then, the images were observed using a magneto-optical Kerr microscopy. Obtained images reveal that the contrast ratio of the area without and with the optical filters changed from 55:96 to 49: 109. The contrast was improved by using the optical filters. It was also confirmed that the observation of the magnetic domains is possible under external magnetic fields.