This page describes in a little more details several projects I participated in during my stay in the University of Alberta, Naval Research Laboratory and the recent work in  the University of California Riverside (UCR).

The Recording Head testing. What is a recording head? It's a unit that writes the information to and reads it from a hard drive in your computer. A recording head is a complex lithographically patterned multilayer thin film structure with active elements of submicron dimensions, but for the sake of simplicity it can be represented as a combination of a tiny horseshoe electromagnet and a sensor that changes its resistance when being penetrated by a magnetic field. The entire assembly flies atop the disk, and the magnet locally flips the magnetization of ferromagnetic medium back and forth when needed to write a bit. The sensor on the other hand, reads the stray field of these locally magnetized areas thus retrieving the stored information.

The temporal profile of the magnetization change at the very tip of the horseshoe magnet (Write Poles) as well as spatial distribution of the pole magnetization are of vital importance for the  R&D teams. Fortunately, the Time Resolved Scanning Kerr Microscopy (TR-SKM) technique allows to map both of them. Typical distribution of magnetization in the Air Bearing Surface plane (the one seen by the recording medium) is shown above. The magnetization and hence the magnetic field has the strongest gradient rght across the gap of the electromagnet.

I tested the Write performance of numerous commercial and prototype heads in collaboration with Read-Rite (then Western Digital), Quantum (subsequently Maxtor and Seagate) and Seagate (Minneapolis) corporations. This collaboration lasted for four years through my Ph. D. studies. The influence of certain aspects of the head design to its Write performance is reported in this publication.

In my current study in the University of California Riverside (UCR) I return to the recording head-and-media design and characterization, but from the medium rather than heads perspective.