Residual Information in Magnetic Memory Devices

Abstract

A review of the magnetic phenomena that cause residual information in magnetic memory devices is presented. The types of devices discussed will be particulate medium devices, thin films, and core memories. Residual information is defined as any magnetic information that can be detected by laboratory techniques after normal clearing of the memory device. Some of the magnetization processes that lead to residual information problems are anhysteretic remanent magnetization, exchange anisotropy, thermal remanent magnetization, skew effects, magnetization creep, and partial switching. An attempt is made to relate these magnetization processes to the demagnetization techniques in magnetic memory devices.