Raman scattering study of temperature- and field-dependent magnetic polaron formation in (Eu,Gd)O

We use Raman scattering to investigate magnetic polarons and spin-career interaction effects in the (Eu, Gd)O system. Raman scattering studies reveal great richness in the phase behavior of this system: a spin-fluctuation-dominated paramagnetic (PM) phase regime for T > T* > Tc, a two-phase regime for T < T* in which magnetic polarons develop below T* and coexist with a remnant of the PM phase, and an inhomogeneous ferromagnetic phase regime for T < Tc. We will discuss how these phase regimes evolve as functions of magnetic field, temperature, and Gd-substitution, and will compare the results with less disordered systems such as EuB₆.