Abstract
We use point-contact spectroscopy (PCS) to probe () and . For we detect orbital fluctuations above while for these fluctuations start below . Co doping preserves the orbital fluctuations while K doping suppresses it. The fluctuations are only seen at those dopings and temperatures where an in-plane resistive anisotropy is known to exist. We predict an in-plane resistive anisotropy of above . Our data are examined in light of the recent work by Lee and Phillips (arXiv:1110.5917v2). We also study how joule heating in the PCS junctions impacts the spectra. Spectroscopic information is only obtained from those PCS junctions that are free of heating effects while those PCS junctions that are in the thermal regime display bulk resistivity phenomena.
- Received 12 January 2012
DOI:https://doi.org/10.1103/PhysRevB.85.214515
©2012 American Physical Society