  Spin torque and spin Hall effect nanooscillators generate high intensity spin
wave auto oscillations on the nanoscale enabling novel microwave applications
in spintronics, magnonics, and neuromorphic computing. For their operation,
these devices require externally generated spin currents either from an
additional ferromagnetic layer or a material with a high spin Hall angle. Here
we demonstrate highly coherent field and current tunable microwave signals from
nanoconstrictions in single 15 and 20 nm thick permalloy layers. Using a
combination of spin torque ferromagnetic resonance measurements, scanning
microBrillouin light scattering microscopy, and micromagnetic simulations, we
identify the autooscillations as emanating from a localized edge mode of the
nanoconstriction driven by spin orbit torques. Our results pave the way for
greatly simplified designs of auto oscillating nanomagnetic systems only
requiring a single ferromagnetic layer.
