Thermal destruction of spin-polaron bands in the narrow-gap correlated semiconductors FeGa3 and FeSb2.

We report muon spin rotation spectra in the narrow-gap semiconductors FeGa(3) and FeSb(2) consistent with a narrow band of small spin polarons (SPs). The characteristic sizes obtained for these SPs are R(FeGa(3)) ≈ 0.3-0.

Bound magnetic polarons in the 3d-electron ferromagnetic spinel semiconductor CdCr2Se4.

Muon spin rotation/relaxation spectroscopy has been employed to study electron localization into a bound magnetic polaron around the positive muon in the 3d magnetic spinel semiconductor CdCr2Se4 at temperatures up to 300 K (far above the ferromagnetic transition at Tc = 130 K) in magnetic fields up to 7 T. Electron localization into a magnetic polaron occurs due to its strong exchange interaction with the magnetic 3d electrons of local Cr(3 +) ions, which confines its wavefunction to within R≈0.3 nm, allowing significant overlap with both the nearest and the next nearest shells of Cr ions.

Spin polarons in the correlated metallic pyrochlore Cd2Re2O7.

Muon spin rotation spectroscopy reveals localized electron states in the geometrically frustrated metallic pyrochlore Cd2Re2O7 at temperatures from 2 to 300 K in transverse magnetic fields up to 7 T. Two distinctive types of localized states, with characteristic radii of about 0.5 and 0.