Abstract
We present a unified approach to describe the combined behavior
of the atomic and magnetic degrees of freedom in magnetic materials.
Using Monte Carlo simulations directly combined with first principles
the Curie temperature can be obtained ab initio in good agreement
with experimental values.
The large scale constrained first principles calculations have been used
to construct effective potentials for both the atomic and magnetic degrees
of freedom that allow the unified study of influence of phonon-magnon coupling
on the thermodynamics and dynamics of magnetic systems.
The MC calculations predict the specific heat of iron in near perfect
agreement with experimental results from 300K to above Tc and allow
the identification of the importance of the magnon-phonon interaction
at the phase-transition. Further Molecular Dynamics and Spin Dynamics
calculations elucidate the dynamics of this coupling and open the potential
for quantitative and predictive descriptions of dynamic structure factors
in magnetic materials using first principles derived simulations.
