Magnetoresistive Detector for Bubble Domains

Publisher Website
Google Scholar
Abstract
This paper describes a simple Permalloy magnetoresistive readout transducer for detecting magnetic bubble domains. The advantages over inductive detection are a large increase in signal and an independence of bubble velocity. The advantages over Hall effect detection are simpler fabrication and higher efficiency. The detector is a strip of thin Permalloy film with two contacts, both of which can be deposited onto the same overlay used for bubble propagation. As an example, a 250 Å×38 μ× 138‐μ device (52 Ω) was used with a measuring current of 7 mA to give a 2.3‐mV signal when detecting 138‐μ diameter bubbles in TmFeO3. The response was constant up to the maximum data rate allowed by the bubble domain, in this case, 106 bits/sec in DyFeO3. The detector itself can switch in less than 10−8 sec. It can be used when conducting strip lines are used for bubble propagation, and also when a rotating field and Permalloy overlay are used. Optimum device placement and shape, as well as ultimate limitations, are discussed in terms of the stray field contours of the bubbles.

This publication has 7 references indexed in Scilit: