Probing the magnetic moment of FePt micromagnets prepared by focused ion beam milling

Overweg, H.C. and den Haan, A.M.J. and Eerkens, H.J. and Alkemade, P.F.A. and La Rooij, A.L. and Spreeuw, R. J.C. and Bossoni, L. and Oosterkamp, T.H. (2015) Probing the magnetic moment of FePt micromagnets prepared by focused ion beam milling. Applied Physics Letters, 107 (7). 072402. ISSN 0003-6951 (https://doi.org/10.1063/1.4928929)

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Abstract

We investigate the degradation of the magnetic moment of a 300 nm thick FePt film induced by Focused Ion Beam (FIB) milling. A 1 μm × 8 μm rod is milled out of a film by a FIB process and is attached to a cantilever by electron beam induced deposition. Its magnetic moment is determined by frequency-shift cantilever magnetometry. We find that the magnetic moment of the rod is μ = 1.1 ± 0.1 × 10-12 Am2, which implies that 70% of the magnetic moment is preserved during the FIB milling process. This result has important implications for atom trapping and magnetic resonance force microscopy, which are addressed in this paper.