title: Controlling the phase locking of stochastic magnetic bits for ultra-low power computation.
abstract: When fabricating magnetic memories, one of the main challenges is to maintain the bit stability while downscaling. Indeed, for magnetic volumes of a few thousand nm(3), the energy barrier between magnetic configurations becomes comparable to the thermal energy at room temperature. Then, switches of the magnetization spontaneously occur. These volatile, superparamagnetic nanomagnets are generally considered useless. But what if we could use them as low power computational building blocks? Remarkably, they can oscillate without the need of any external dc drive, and despite their stochastic nature, they can beat in unison with an external periodic signal. Here we show that the phase locking of superparamagnetic tunnel junctions can be induced and suppressed by electrical noise injection. We develop a comprehensive model giving the conditions for synchronization, and predict that it can be achieved with a total energy cost lower than 10(-13) J. Our results open the path to ultra-low power computation based on the controlled synchronization of oscillators.
authors.affiliation: Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France.|Centre de Nanosciences et de Nanotechnologies, CNRS, Univ Paris-Sud, Université Paris-Saclay, 91405 Orsay France.
authors.forename: Alice
authors.initials: A
authors.lastname: Mizrahi
authors.affiliation: Centre de Nanosciences et de Nanotechnologies, CNRS, Univ Paris-Sud, Université Paris-Saclay, 91405 Orsay France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Locatelli
authors.affiliation: Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France.
authors.forename: Romain
authors.initials: R
authors.lastname: Lebrun
authors.affiliation: Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Cros
authors.affiliation: Spintronics Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Fukushima
authors.affiliation: Spintronics Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kubota
authors.affiliation: Spintronics Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Yuasa
authors.affiliation: Centre de Nanosciences et de Nanotechnologies, CNRS, Univ Paris-Sud, Université Paris-Saclay, 91405 Orsay France.
authors.forename: Damien
authors.initials: D
authors.lastname: Querlioz
authors.affiliation: Unité Mixte de Physique CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, 91767 Palaiseau, France.
authors.forename: Julie
authors.initials: J
authors.lastname: Grollier