Probing the Dynamics of Pressure- and Magnetic Field -Tuned Transitions in Strongly-Correlated Electron Systems: Raman Scattering Studies
Third, I present Raman scattering measurements of (Eu,Gd)O and (Eu,La)B 6 as functions of doping, B isotope, magnetic field, and temperature. Our results reveal a variety of distinct regimes as a function of decreasing T: (i) a paramagnetic semimetal regime, characterized by a collision-dominated electronic scattering response whose scattering rate Gamma decreases with decreasing temperature; (ii) a spin-disorder scattering regime, characterized by a collision-dominated electronic scattering response whose scattering rate Gamma scales with the magnetic susceptibility; (iii) a magnetic polaron (MP) regime, in which the development of an H = 0 spin-flip Raman response betrays the formation of magnetic polarons above the Curie temperature Tc; and (iv) a ferromagnetic metal regime, characterized by a flat electronic continuum response.
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign