Sensing magnetic nanoparticles using nano-confined ferromagnetic resonances in a magnonic crystal

• Published in: Applied physics letters Vol. 106; no. 23
• Main Authors: Metaxas, P. J., Sushruth, M., Begley, R. A., Ding, J., Woodward, R. C., Maksymov, I. S., Albert, M., Wang, W., Fangohr, H., Adeyeye, A. O., Kostylev, M.
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 08-06-2015
• Subjects: Applied physics; Crystals; Dependence; Ferromagnetic resonance; Ferromagnetism; Mode localization; Nanoparticles
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4922392

We experimentally demonstrate the use of the magnetic-field-dependence of highly spatially confined, GHz-frequency ferromagnetic resonances for the detection of magnetic nanoparticles using an anti-dot-based magnonic crystal. The stray magnetic fields of nanoparticles within the anti-dots modify nano-confined ferromagnetic resonances in the surrounding periodically nanopatterned magnonic crystal, generating easily measurable resonance peak shifts. The shifts are comparable to the resonance linewidths for high anti-dot filling fractions with their signs and magnitudes dependent upon the mode localization, consistent with micromagnetic simulation results. This is an encouraging result for the development of frequency-based nanoparticle detectors for nano-scale biosensing.