Field-dependence of microscopic probes in magnetic force microscopy

Abstract

We present a technique for characterizing the magnetic state of a magnetic force microscopy (MFM) probe as a function of uniform external magnetic field H. A local magnetic field is generated by micron-scale current carrying conductors and directly imaged by MFM. As H alters the magnetic state of the probe, changes in image contrast yield componentwise measures of the tip’s net magnetic moment m, tip hysteresis loops and coercivities, and possible orientations (vertical vs lateral) of remanent states mr used for most MFM imaging. Results are presented for a variety of thin-film probes.

Quantification of magnetic force microscopy images using combined electrostatic and magnetostatic imaging

“…1 ͑left͒, we obtain the effective moment for the probe, m z ϭ2.22 ϫ10 Ϫ15 A m 2 (2.22ϫ10 Ϫ12 emu). This value is consistent with previous estimates, 4,6 albeit somewhat lower, which could be attributed to differences on the specific probes used. As a plausibility check, we can compute the magnetization of the probe by dividing m z with effective magnetic volume.…”

“…Unfortunately, due to space constraints in this article, we refer the reader to the literature. Previous approaches have involved the imaging of a standardized system, such as a metal strip 3,4 or single-crystal surfaces 5 or the usage of sophisticated methods to measure the magnetic moment of the probe and compare the acquired data with various models for the probe. 6,7 There are, however, no methods that prescribe a self-contained calibration procedure of both the probe's mechanical and magnetic characteristics by utilizing only the measurements of the instrument itself.…”

Atomic Force Microscopy and Magnetic Force Microscopy Study of Model Colloids

“…Single-domain superparamagnetic magnetite particles have not been studied before with this technique. Previous studies on MFM were focused mainly on magnetic recording media (5) and multidomain magnetic materials (6,7) as well as on tip characterization (8) and image interpretation (9,10). Closer to our work, there were reported the imaging and remagnetization of Co magnetic dots (with lateral dimensions of 140 × 250 nm) (11) and imaging and magnetic moment estimation of magnetotactic bacteria (50 nm in length and 17.5 nm in radius, if modeled as a cylinder) (12).…”

“…Another discussion is necessary here: the magnetometer measures the entire magnetic layer deposited on the cantilever and cantilever substrate, not only the magnetic volume relevant for imaging the sample. This results in overestimation of the coercive field [8].…”

Materials Degradation and Detection (MD2): Deep Dive Final Report

“…This has the benefit of allowing direct comparison with meso-scale phase field computer models, which compute "voxel-by-voxel" magnetization. Magnetometry (or susceptometry) is obtainable from both MFM (Babcock et al 1996;Zhu et al 2003;Sorop et al 2003) and MOKE microscopy (Choe et al 2002;Sato and Ishibashi 2008) data. MOKE microscopy/ magnetometry is routinely used for combinatorial screening of magnetic compounds (Zhao et al 2004).…”