In an effort to elucidate the origin of the Curie-like paramagnetism that is generic for heavily overdoped cuprates, we have performed high-transverse-field muon spin rotation (TF-μSR) measurements of La 2-xSr xCuO 4 single crystals over the Sr content range 0.145≤x≤0.33. We show that the x dependence of the previously observed field-induced broadening of the internal magnetic field distribution above the superconducting transition temperature T c reflects the presence of two distinct contributions. One of these becomes less pronounced with increasing x and is attributed to diminishing antiferromagnetic correlations. The other grows with increasing x, but decreases above x∼0.30, and is associated with the Curie-like term in the bulk magnetic susceptibility χ. In contrast to the Curie-like term, however, this second contribution to the TF-μSR linewidth extends back into the underdoped regime. Our findings imply a coexistence of antiferromagnetically correlated and paramagnetic moments, with the latter becoming dominant beyond x∼0.185. This suggests that the doped holes do not neutralize all Cu spins via the formation of Zhang-Rice singlets. Moreover, the paramagnetic component of the TF-μSR linewidth is explained by holes progressively entering the Cu 3d x2-y2 orbital with doping.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2012 Aug 29|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics