Imaging of Bit-Patterned Media with Magnetic Force Microscopy

By AZoNano Staff Writers

Table of Content

Measurement of Switching Field Distributions
About NanoScan AG


Bit-patterned media (BPM) includes topographical dots written into the magnetic layer. The magnetic bit is confined and decoupled from its neighbours by the physical structure of the dots, and thus promotes smaller bits sizes.

BPM is expected to be used in next generation magnetic recording media. This article describes the magnetic force microscopy (MFM) measurements on BPM with a centre-to-centre pitch of 50nm.

Measurement of Switching Field Distributions

Figure 1. Series of MFM images taken of the same array with increasing external magnetic field.

The above images belong to a range of MFM images acquired at a temperature of 10K with increasing and variable external magnetic field (Figure 1). The NanoScan PPMS®-AFM shows exceptional position stability even under the effect of external magnetic fields. As a result, no software or hardware shift-correction was required.

Figure 2. MFM images of the same area at varying temperatures; the last image is an AFM image displaying the sample surface topography.

The dark dots are magnetised parallel to the tip field, whilst the bright dots are magnetised anti-parallel. The images allowed in measuring the switching field distribution (SFD) for a local area. Images in Figure 2 belong to a range of MFM images acquired at varying temperatures. In this measurement, the temperature dependence of the SFD was examined.

Owing to the unique positional reproducibility, it was possible to replace the cantilever and obtain an nc-AFM image at the same position by means of a non-magnetic tip.


To sum up, MFM Imaging of BPM was possible due to the excellent position stability of NanoScan PPMS®-AFM even under the effect of increasing external magnetic field.

About NanoScan AG

With excellent know-how in the fast growing field of nanoscience, the main focus of NanoScan AG is on research and development of high-resolution and versatile magnetic and non-contact scanning force microscopes. These instruments are especially designed to fulfill the present and future analytical needs on nanometer-sized surface structures.

This information has been sourced, reviewed and adapted from materials provided by NanoScan AG.

For more information on this source, please visit NanoScan AG.

Date Added: Dec 18, 2013 | Updated: Feb 6, 2014
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