2011/09/22 by K. Shen, M. W. Wu
Materials Science · Physics and Astronomy · #Condensed matter physics #Curie temperature #Ferromagnetism #Magnetic and transport properties of perovskites and related materials #Magnetic field #Magnetic properties of thin films #Physics #Quantum mechanics #Relaxation (psychology) #Spin (aerodynamics) #Spin wave #Thermodynamics #Zeeman effect #ZnO doping and properties #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.85.075206
published as Phys. Rev. B 85, 075206 (2012) · 10 pages, 7 figures
arxiv created 2011/09/22 · openalex publication_date 2012/02/09 · arxiv updated 2012/02/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We investigate the temperature dependence of the coefficients in the Landau-Lifshitz-Gilbert equation in ferromagnetic GaMnAs by employing the Zener model. We first calculate the hole spin relaxation time based on the microscopic kinetic equation. We find that the hole spin relaxation time is typically several tens of femtoseconds and can present a nonmonotonic temperature dependence due to the variation of the interband spin mixing, influenced by the temperature-related Zeeman splitting. With the hole spin relaxation time, we are able to calculate the coefficients in the Landau-Lifshitz-Gilbert equation, such as the Gilbert damping, nonadiabatic spin torque, spin stiffness, and vertical spin stiffness coefficients. We find that the nonadiabatic spin torque coefficient \ensuremathβ is around 0.1\ensuremath-0.3 at low temperature, which is consistent with the experiment [J.-P. Adam et al., Phys. Rev. B 80, 193204 (2009)]. As the temperature increases, \ensuremathβ monotonically increases. We show that the Gilbert damping coefficient \ensuremathα increases with temperature below the Curie temperature, showing good agreement with the experiments [J. Sinova et al., Phys. Rev. B 69, 085209 (2004); Kh. Khazen et al., Phys. Rev. B 78, 195210 (2008)]. Moreover, we also calculate the temperature dependences of the spin stiffness and vertical spin stiffness.