The magnetization of a magnetic material can be reversed by using electric currents that transport spin angular momentum. In the reciprocal process a changing magnetization orientation produces currents that transport spin angular momentum. Understanding how these processes occur reveals the intricate connection between magnetization and spin transport, and can transform technologies that generate, store or process information via the magnetization direction [1,2]. In this talk I will explain how currents can generate torques that affect the magnetic orientation in a variety of magnetic materials and structures. I will also discuss recent results from my group on the current-induced excitation of spin-waves in nanometer scale contacts to ferromagnetic thin films [3,4].

[1] A. Brataas, A. D. Kent and H. Ohno, “Current-Induced Torques in Magnetic Materials”, Nature Materials 11, 372 (2012); doi:10.1038/nmat3311

[2] A. D. Kent and D. C. Worledge, “A new spin on magnetic memories,” Nature Nanotechnology 10, 187 (2015); doi:10.1038/nnano.2015.24

[3] F. Macia, D. Backes and A. D. Kent “Stable magnetic droplet solitons in spin-transfer nanocontacts,” Nature Nanotechnology 9, 992 (2014); doi:10.1038/nnano.2014.255

[4] D. Backes, F. Macià, S. Bonetti, R. Kukreja, H. Ohldag and A. D. Kent, “Direct Observation of a Localized Magnetic Soliton in a Spin-Transfer Nanocontact,” Physical Review Letters 115, 127205 (2015); http://dx.doi.org/10.1103/PhysRevLett.115.127205