Blasting sensors

A new process for adjusting the resistance of semiconductor devices by carpeting a small area of the device with tiny pits may be the key to a new class of magnetic sensors, enabling new, ultra-dense data storage devices.

The new process has been developed by researchers at the National Institute of Standards and Technology (NIST) in the US.

Tiny magnetic sensors in modern disk drives are a sandwich of two magnetic layers separated by a thin buffer layer. The layer closest to the disk surface is designed to switch its magnetic polarity quickly in response to the direction of the magnetic “bit” recorded on the disk under it. The sensor works by measuring the electrical resistance across the magnetic layers, which changes depending on whether the two layers have matching polarities.

As manufacturers strive to make disk storage devices smaller and more densely packed with data, sensor designers are attempting to build sensors based on Giant Magneto-Resistance (GMR) or Magnetic Tunnel Junction (MTJ) technologies.