Spin-State Transition in the Fe Pnictides
Spin-State Transition in the Fe Pnictides
We report an Fe $K\ensuremath{\beta}$ x-ray emission spectroscopy study of local magnetic moments in the rare-earth doped iron pnictide ${\mathrm{Ca}}_{1\ensuremath{-}x}{\mathrm{RE}}_{x}{\mathrm{Fe}}_{2}{\mathrm{As}}_{2}$ ($\mathrm{RE}=\mathrm{La}$, Pr, and Nd). In all samples studied the size of the Fe local moment is found to decrease significantly with temperature and goes from $\ensuremath{\sim}0.9{\ensuremath{\mu}}_{B}$ at $T=300\text{ }\text{ }\mathrm{K}$ …