Magnetization Dynamics of Spin to Charge conversion in Nickel Nanoparticles*

In this talk, we discuss the study of tunneling magnetoresistance and magnetic relaxation in single nickel nanoparticles using electron tunneling at 30mK. Our key observation is a strong magnetic field dependence of the effective charge noise. This effect is explained in terms of spin to charge conversion. From the rms of the charge noise we find the rms of the magnetization, and its magnetic field dependence. The magnetization relaxation time peaks at magnetic field of approximately 1T, with the relaxation time of T1=ms at that field. We will discuss the latest results on implementation of nickel nanoparticles with long spin relaxation time in these in spin-transfer torque switching.