Observation of Magnetic Radial Vortex Nucleation in a Multilayer Stack with Tunable Anisotropy

• Main Authors: Karakas, Vedat, Gokce, Aisha, Habiboglu, Ali Taha, Arpaci, Sevdenur, Ozbozduman, Kaan, Cinar, Ibrahim, Yanik, Cenk, Tomasello, Riccardo, Tacchi, Silvia, Siracusano, Giulio, Carpentieri, Mario, Finocchio, Giovanni, Hauet, Thomas, Ozatay, Ozhan
• Format: Journal Article
• Language: English
• Published: 08-09-2017
• Subjects: Physics - Mesoscale and Nanoscale Physics
• DOI: 10.48550/arxiv.1709.02876

Recently discovered exotic magnetic configurations, namely magnetic solitons
appearing in the presence of bulk or interfacial Dzyaloshinskii-Moriya
Interaction (i-DMI), have excited scientists to explore their potential
applications in emerging spintronic technologies such as race-track magnetic
memory, spin logic, radio frequency nano-oscillators and sensors. Such studies
are motivated by their foreseeable advantages over conventional micro-magnetic
structures due to their small size, topological stability and easy spin-torque
driven manipulation with much lower threshold current densities giving way to
improved storage capacity, and faster operation with efficient use of energy.
In this work, we show that in the presence of i-DMI in Pt/CoFeB/Ti multilayers
by tuning the magnetic anisotropy (both in-plane and perpendicular-to-plane)
via interface engineering and postproduction treatments, we can stabilize a
variety of magnetic configurations such as N\'eel skyrmions, horseshoes and
most importantly for the first time, the recently predicted isolated radial
vortices at room temperature and under zero bias field. Especially, the radial
vortex state with its absolute convergence to or divergence from a single point
can potentially offer exciting new applications such as particle
trapping/detrapping in addition to magnetoresistive memories with efficient
switching, where the radial vortex state can act as a source of spin-polarized
current with radial polarization.