Eur. Phys. J. B 59, 435-445 (2007)
https://doi.org/10.1140/epjb/e2007-00051-5

Analytical study of magnetization dynamics driven by spin-polarized currents

¹ Istituto Nazionale di Ricerca Metrologica, Strada delle Cacce 91, 10135 Torino, Italy
² Dipartimento di Ingegneria Elettrica, Università di Napoli “Federico II”, via Claudio 21, 80125 Napoli, Italy
³ Department of Electrical and Computer Engineering, University of Maryland, College Park, MD, 20742, USA
⁴ Dipartimento per le Tecnologie, Università di Napoli “Parthenope”, via Medina 40, 80133 Napoli, Italy

Corresponding author: ^a bonin@inrim.it

Received: 29 September 2006
Revised: January 1900
Published online: 16 February 2007

Abstract

An analytical approach is presented for the study of magnetization dynamics driven by spin-polarized currents. Two cases are considered: (i) magnetic layers with in-plane uniaxial anisotropy; (ii) magnetic layers with uniaxial anisotropy and applied field perpendicular to the layer plane. Theoretical predictions are obtained for the existence of stationary modes and self-oscillations of magnetization by solving the deterministic Landau-Lifshitz-Gilbert equation with Slonczewski spin-torque term. Thermal fluctuations are studied by deriving the corresponding Fokker-Planck equation for the magnetization probability distribution. Analytical procedures to estimate the effective potential barrier separating self-oscillatory regimes and/or stationary modes are proposed.