A permalloy detector for orthoferrite domains

A Permalloy detector using the pseudo or planar Hall effect has been developed for electrical readout of cylindrical domains in the orthoferrites. It consists of four gold leads attached to a Permalloy dot nominally 0.03 µm thick and 50 µm in diameter. Source resistance including gold leads was from 10 to 15 ohms. For 20-mA input current and domains approximately 60 µm in diameter, the detector yielded 0.8-mV signals in quasi-static operation. The speed capability of the Permalloy detector should be well above that of propagating domain devices.