Analysis of Ferro- and Antiferromagnetic Memory Bits by Scanning NV Magnetometry

Storing information in magnetic bits requires excellent control over their nanoscale magneticproperties. A prime example of this challenge are STT-MRAM (spin transfer torque magnetic random accessmemory) devices - which have rather high failure rates. In order to investigate the sources of potential failure, atechnique that can resolve small magnetic fields with high spatial resolution is required. The request is evenmore urgent for next-generation magnetic memory materials, such as antiferromagnets, which generate evensmaller magnetic signals.<br/>Scanning NV magnetometry (SNVM) is an emerging quantum sensing technique that offers the requiredsensitivity. Here, we will look at the local magnetic properties of bits in state-of-the-art STT-MRAM devicesusing scanning-NV magnetometry [1]. Furthermore, we will demonstrate magnetic images of a few hotcandidate materials for future magnetic memory devices including antiferromagnetic chromia, BFO [2] andultra-scaled CoFeB nanowires [3]. We will reveal magnetic textures that are undetectable with more standardcharacterization techniques and discuss implications on device fabrication.<br/>References:<br/>[1] P. Rickhaus et.al., https://arxiv.org/abs/2306.15502<br/>[2] H. Zhong et al, Phys. Rev. Applied 17, 044051 (2022)<br/>[3] U. Celano et al, Nano Lett. 21, 24, 10409–10415 (2021)