ABSTRACT
Spin torque oscillators (STOs) comprise a diverse class of nanomagnetic devices that exhibit ultrawide operating frequencies and modulation rates. Furthermore, their manufacturing processes are compatible with radio frequency (RF) complementary metal- oxide semiconductor (CMOS) fabrication standards, which make them particularly well-suited for easy integration into existing and future technologies. STOs combine several spintronic and nanomagnetic phenomena for their operation, such as giant magnetoresistance (GMR), tunneling magnetoresistance (TMR), spin transfer torque (STT), and, depending on device architecture and the constituent magnetic materials employed, a plethora of possible fundamentally intriguing magnetodynamic modes. This chapter summarizes some of the most recent work since the first experimental observation of propagating spin waves in nanocontact STOs (NC-STOs) was published in 2011. A central theme has been the critical role of the inhomogeneous Oersted field on the magnetodynamics, which has shown to give rise to not only spin wave localization but also asymmetric spin wave propagation. This asymmetric spin wave propagation has far- reaching consequences.
