NMR as a local probe of magnetic anisotropy: The possibility of orbital ordering and orbital liquid states in colossal magnetoresistance manganites -art. no. 180406

La-139 rf enhancement experiments are shown to be an excellent tool for det ecting changes of the local magnetic anisotropy in colossal magnetoresistan ce manganites. Based on this, we discuss the possibility of orbital orderin g in ferromagnetic (FM) La1-xCaxMnO3, and provide evidence about the format ion of an unusual kind of phase separation in the low temperature regime of the FM conductive (FMC) phase for 0.25 less than or equal tox<0.5. We show that by lowering temperature, an extra NMR signal is formed in the FMC pha se, which originates from regions with vanishingly small magnetic anisotrop y. We anticipate that this feature is due to the formation of regions with strong orbital fluctuations within an orbitally frozen matrix.