Magnetic ordering and transport properties of PrBa2Cu4O8

[[abstract]]We present studies of the thermal, magnetic, and electrical transport properties of polycrystalline PrBa2Cu4O8 prepared at ambient oxygen pressure. Measurements of the low temperature specific heat C(T) and magnetic susceptibility X(T) show similar results as in PrBa2Cu4O8 an anomaly observed at 17 K in C(T) and dχ/dT may be due to the antiferromagnetic ordering of the Pr sublattice. The upper limit of the entropy associated with the magnetic ordering is estimated to be 6.6 J/mol K. The free magnetic moment from a simple Curie-Weiss fit is 3.11 μg. These similarities in magnetic properties of PrBa2Cu3O7 and PrBa2Cu4O8 suggest that the magnetic coupling mechanism might be mainly associated with the CuO2, planes. The resistivity p(T) is nearly metallic from 1.5 to 300 K. Comparisons of samples prepared by different methods suggest that the anomaly in resistivity around 200 K may be extrinsic. The behavior of p(T) is rather puzzling and cannot be explained simply by a dimensional crossover of charge transport arising from the double CuO2 chains. Other similarities and differences of the mentioned physical properties between PrBa2Cu4O8 and PrBa2Cu4O8 are stressed as well[[fileno]]2010102010072[[department]]物理