| AVS 57th International Symposium & Exhibition | |
| MEMS and NEMS | Thursday Sessions |
| Session MN-ThM |
| Session: | Multi-scale Interactions of Materials at the Micro- and Nano-scale |
| Presenter: | J.G. Longenecker, Cornell University |
| Authors: | J.G. Longenecker, Cornell University S.A. Hickman, Cornell University E.W. Moore, Cornell University S.G. Lee, Cornell University S.J. Wright, Cornell University L.E. Harrell, United States Military Academy J.A. Marohn, Cornell University |
| Correspondent: | Click to Email |
Mechanical detection of magnetic resonance opens up exciting possibilities for characterizing soft materials and biomolecules with elemental specificity at nanometer-scale, and potentially atomic-scale, resolution. Achieving atomic-scale resolution requires using cantilevers with a low minimum detectable force at small tip-sample separations and fabricating magnetic tips with only a few nanometers of damage at the leading edge. We address these challenges by 1) fabricating cantilevers with overhanging magnetic tips, 2) protecting the nanomagnet leading edge by atomic layer deposited (ALD) alumina, and 3) characterizing the extent and chemical mechanism of damage by nanometer-resolution electron energy loss spectroscopy (EELS).
After determining by EELS analysis that the nickel magnet leading edge incurred substantial damage during processing, we introduced tantalum and ALD alumina interdiffusion barriers into our forty-two step fabrication process. We demonstrate that these modifications have significantly reduced the damage layer thicknesses. The nanomagnet grain structure, point-by-point relative atomic concentrations at the leading edge, and magnetization are determined by high-resolution transmission electron microscopy (TEM), EELS, and frequency-shift cantilever magnetometry, respectively. We will also detail ongoing work to reduce the number of processing steps after magnet deposition, which could greatly improve magnet yield and quality. Our findings suggest that fabricating a cantilever suitable for single proton detection, while a materials processing challenge, should be possible.