Magnetic properties of lithographically patterned thin film magnetic elements for magnetic random access memory applications

Abstract

Interference lithography, together with ion beam etching or lift-off processes, has been utilized to produce large area periodic rectangular patterns. Single layer Co, NiFe, and multilayer Co/Cu/NiFe pseudo spin valve films have been patterned into series of element arrays with different sizes. With the aim of assessing the behavior of future magnetic random access memory (MRAM) devices, the magnetic properties of the patterned elements, including magnetization switching mechanisms, switching field distribution, magnetic thermal stability, and magnetostatic interactions, have been studied using magnetic force microscopy (MFM), SQUID magnetometer, alternating gradient magnetometer (AGM) and vibrating sample magnetometer (VSM). The measured results have been compared with the theoretical shape anisotropy theory to try finding a guideline for controlling magnetic properties of patterned elements.