High-throughput top-down fabrication of uniform magnetic particles

Julia Litvinov, Azeem Nasrullah, Timothy Sherlock, Yi Ju Wang, Paul Ruchhoeft, Richard C. Willson

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

Ion Beam Aperture Array Lithography was applied to top-down fabrication of large dense (108-109 particles/cm2) arrays of uniform micron-scale particles at rates hundreds of times faster than electron beam lithography. In this process, a large array of helium ion beamlets is formed when a stencil mask containing an array of circular openings is illuminated by a broad beam of energetic (5-8 keV) ions, and is used to write arrays of specific repetitive patterns. A commercial 5-micrometer metal mesh was used as a stencil mask; the mesh size was adjusted by shrinking the stencil openings using conformal sputter-deposition of copper. Thermal evaporation from multiple sources was utilized to form magnetic particles of varied size and thickness, including alternating layers of gold and permalloy. Evaporation of permalloy layers in the presence of a magnetic field allowed creation of particles with uniform magnetic properties and pre-determined magnetization direction. The magnetic properties of the resulting particles were characterized by Vibrating Sample Magnetometry. Since the orientation of the particles on the substrate before release into suspension is known, the orientation-dependent magnetic properties of the particles could be determined.

Original languageEnglish (US)
Article numbere37440
JournalPloS one
Volume7
Issue number5
DOIs
StatePublished - May 31 2012

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)
  • General

Fingerprint Dive into the research topics of 'High-throughput top-down fabrication of uniform magnetic particles'. Together they form a unique fingerprint.

  • Cite this

    Litvinov, J., Nasrullah, A., Sherlock, T., Wang, Y. J., Ruchhoeft, P., & Willson, R. C. (2012). High-throughput top-down fabrication of uniform magnetic particles. PloS one, 7(5), [e37440]. https://doi.org/10.1371/journal.pone.0037440