We report on a comparative study of the transport properties of lightly La-doped layered CaO (CaMnO 3 ) m (mϭ1, 2, and ϱ͒ and similar Mn 3ϩ /Mn 4ϩ ratios. In contrast to the large and rather nonsystematic variations of the resistivity (T) for samples with the same doping and various m, the absolute thermopower ͑S͒ exhibits remarkable systematics. In the paramagnetic ͑PM͒ state, S varies linearly with temperature and its extrapolation to Tϭ0 has a finite intercept. The intercept and the slope of these lines vary systematically with m. In particular, within the experimental error, the inverse slopes of the straight lines increase linearly with 1/m, which in its turn varies linearly with the average number of Mn-Mn near neighbors. The implications of this simple systematics are discussed using a model developed by Cutler and Mott ͓Phys. Rev. 181, 1336 ͑1968͔͒ for transport by activated hopping of carriers obeying nondegenerate statistics. This model ͑or a possible extension into the semidegenerate regime͒ leads also to a simple, qualitative interpretation of S(T) of these materials on crossing the Néel temperature (T N ) from the PM state and below T N .
We characterize the spontaneous magnetic field, and determine the associated temperature T(g), in the superconducting state of (Ca(x)La(1-x)) (Ba(1.75-x)La(0.25+x)) Cu(3)O(y) using zero and longitudinal field muon spin resonance measurements for various values of x and y. Our major findings are (i) T(g) and T(c) are controlled by the same energy scale, (ii) the phase separation between hole poor and hole rich regions is a microscopic one, and (iii) spontaneous magnetic fields appear gradually with no moment size evolution.
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