Sidney Tsai
MRS Fall Meeting 2023
A nano-structured magnetic tunnel junction (MTJ) operating in superparamagnetic limit with easy-plane dominant anisotropy can convert thermal fluctuation of the magnetic moments into electric tunnel conductance fluctuation with nearly white spectrum beyond a GHz in bandwidth and could be useful as a compact electronic entropy source for computing. We explore the base-line behavior of such easy-plane dominant MTJs using materials and fabrication routes similar to spin-transfer-torque magnetic random-access memory (STT-MRAM). The measurement observations, both on analog time-series and the corresponding binary digitized bit-streams are analyzed for their randomness and spectrum content, and compared to behaviors generated from a 4-moment coupled macrospin Langevin model in comparable materials and operating parameters space. We show experimentally that stochastic bit-streams can be generated using these MTJs at a bit-rate around 1Gb/sec, and we establish the likely important factors in need for further materials and device optimization – chief of them the reduction of any unintended in-plane magnetic anisotropy energy in such junctions in comparison to thermal energy.
Sidney Tsai
MRS Fall Meeting 2023
Corey Liam Lammie, Hadjer Benmeziane, et al.
Nat. Rev. Electr. Eng.
Samuele Ruffino, Kumudu Geethan Karunaratne, et al.
DATE 2024
Olivier Maher, N. Harnack, et al.
DRC 2023