title: Magnetic droplet nucleation boundary in orthogonal spin-torque nano-oscillators.
abstract: Static and dynamic magnetic solitons play a critical role in applied nanomagnetism. Magnetic droplets, a type of non-topological dissipative soliton, can be nucleated and sustained in nanocontact spin-torque oscillators with perpendicular magnetic anisotropy free layers. Here, we perform a detailed experimental determination of the full droplet nucleation boundary in the current-field plane for a wide range of nanocontact sizes and demonstrate its excellent agreement with an analytical expression originating from a stability analysis. Our results reconcile recent contradicting reports of the field dependence of the droplet nucleation. Furthermore, our analytical model both highlights the relation between the fixed layer material and the droplet nucleation current magnitude, and provides an accurate method to experimentally determine the spin transfer torque asymmetry of each device.
authors.affiliation: Department of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden.|Materials and Nano Physics, School of ICT, KTH-Royal Institute of Technology, Electrum 229, 164 40 Kista, Sweden.
authors.forename: Sunjae
authors.identifier: http://orcid.org/0000-0002-9970-0060
authors.initials: S
authors.lastname: Chung
authors.affiliation: Integrated Devices and Circuits, School of ICT, KTH-Royal Institute of Technology, Electrum, 229, 164 40 Kista, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Eklund
authors.affiliation: Department of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden.|Department of Applied Mathematics, University of Colorado, Boulder, Colorado 80309-0526, USA.|Department of Physics, Division for condensed matter theory, Chalmers University of Technology, Gothenburg 412 96, Sweden.
authors.forename: Ezio
authors.initials: E
authors.lastname: Iacocca
authors.affiliation: Department of Physics, Shahid Beheshti University, Tehran 19839, Iran.
authors.forename: Seyed Majid
authors.initials: SM
authors.lastname: Mohseni
authors.affiliation: Materials and Nano Physics, School of ICT, KTH-Royal Institute of Technology, Electrum 229, 164 40 Kista, Sweden.
authors.forename: Sohrab R
authors.initials: SR
authors.lastname: Sani
authors.affiliation: Department of Mathematics, Yale University, New Haven, Connecticut 06511, USA.
authors.forename: Lake
authors.initials: L
authors.lastname: Bookman
authors.affiliation: Department of Physics, Shahid Beheshti University, Tehran 19839, Iran.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Hoefer
authors.affiliation: Department of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden.
authors.forename: Randy K
authors.initials: RK
authors.lastname: Dumas
authors.affiliation: Department of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden.|Materials and Nano Physics, School of ICT, KTH-Royal Institute of Technology, Electrum 229, 164 40 Kista, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Åkerman