Abstract
Magnetic and transport properties of system have been investigated. A broad maximum in the curve, indicative of low-dimensional antiferromagnetic ordering originated from layers, is observed in the Ca-free sample. With increasing as Ca doping level up to 0.2, the curve remains almost unchanged, while resistivity is reduced by three orders. A higher Ca doping level leads to a drastic change of magnetic properties. In comparison with the samples with , the temperature corresponding to the maximum of is much lower for the sample . The sample shows a small kink instead of a broad maximum and a weak ferromagnetic feature. The electrical transport behavior is found to be closely related to magnetic properties for the sample , 0.25, 0.3, 0.4. It suggests that layers are involved in charge transport, in addition to conducting planes to interpret the correlation between magnetism and charge transport. X-ray photoelectron spectroscopy studies give additional evidence of the the transfer of the holes into the charge reservoir.
1 More- Received 2 January 2004
DOI:https://doi.org/10.1103/PhysRevB.70.054520
©2004 American Physical Society