The electrical response of an individual multiwalled carbon nanotube (MWNT) and its contacts, welded to a coplanar waveguide (CPW), was measured up to 24 GHz using a technique that removes environment effects. This is the first time MWNT contact effects have been systematically isolated from the CPW. Each contact response was quite different and also showed a pronounced sensitivity to ambient light. Adding more contact material clearly changed the high-frequency electrical response and the sensitivity to light.

Cobalt ferrite, CoFe 2 O 4 , thin films are explored as pinning layers for read sensor applications. High ⌬R/R values, 12.8%, and high pinning fields, 1500 Oe, are observed. Unlike other coercivity based pinning layers, the soft properties of the free layer are not compromised. The properties of the cobalt ferrite layers are strongly dependent on the microstructure, which, in turn, depends on the reactive sputtering process.

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We describe a technique to modify batch-fabricated magnetic force microscopy (MFM) tips to allow high resolution imaging of the in-plane components of stray field. A hole with a diameter as small as 20 nm was milled through the magnetic layer at the apex of each tip using a focused ion beam. The tips were magnetized in the direction parallel to the sample plane. The hole at the apex forms a small pole gap, and the MFM signal arises from interaction of the stray field leakage from this gap with magnetic charge distribution of the sample. Data tracks written in recording media have been used to characterize tip performance.