Coexistence of polaronic and band states in a bilayer manganite from two-dimensional reconstruction of magnetic Compton profiles

Abstract

We have measured directional magnetic Compton profiles between [100] and [110] directions in a bilayer manganite at $10\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. The two-dimensional spin momentum distribution of the Mn $3d$ state is reconstructed from them. The result is examined in both terms of molecular orbital and band schemes. The ${e}_{\mathrm{g}}$ type orbitals are dominated by the ${x}^{2}\ensuremath{-}{y}^{2}$ type orbital. The occupation-number density in the $k$ space obtained by the Lock-Crisp-West folding is not explained only by the band picture, and suggests that a polaronic state of ${e}_{\mathrm{g}}$ type electrons coexists in the ferromagnetic metal phase below ${T}_{\mathrm{c}}$.