Performance of magnetoresistive sensors is today mainly limited by their 1/f low-frequency noise. Here, we study this noise component in vortex-based TMR sensors. We compare the noise level in different magnetization configurations of the device, i.e vortex state or uniform parallel or antiparallel states. We find that the vortex state is at least an order of magnitude noisier than the uniform states. Nevertheless, by activating the spin-transfer induced dynamics of the vortex configuration, we observe a reduction of the 1/f noise, close to the values measured in the AP state, as the vortex core has a lower probability of pinning into defect sites. Additionally, by driving the dynamics of the vortex core by a non-resonant rf field or current we demonstrate that the 1/f noise can be further decreased. The ability to reduce the 1/f low-frequency noise in vortex-based devices by leveraging their spin-transfer dynamics thus enhances their applicability in the magnetic sensors' landscape.
@article{arxiv.2012.09616,
title = {Spin-torque Dynamics for Noise Reduction in Vortex-based Sensors},
author = {Mafalda Jotta Garcia and Julien Moulin and Steffen Wittrock and Sumito Tsunegi and Kay Yakushiji and Akio Fukushima and Hitoshi Kubota and Shinji Yuasa and Ursula Ebels and Myriam Pannetier-Lecoeur and Claude Fermon and Romain Lebrun and Paolo Bortolotti and Aurélie Solignac and Vincent Cros},
journal= {arXiv preprint arXiv:2012.09616},
year = {2021}
}