THERMAL-PROPERTIES OF PRBA2CU4O8 PREPARED AT AMBIENT OXYGEN-PRESSURE

Polycrystalline PrBa2Cu4O8 (Pr124) has been prepared at ambient oxygen pressure by nitrite pyrolysis method. Powder x-ray-diffraction patter ns show a nearly single R124 phase. Thermogravimetric analysis indicat es that its thermal stability is distinct from that of Pr123. Specific heat C has been measured from 0.5 to 40 K, and is very similar to tha t of Pr123. A maximum of C occurs around 17 K which could be due to a magnetic ordering. Entropy difference Delta S has been calculated from Delta C/T between Pr124 and Y124. The possible origins of Delta S and the related magnetic properties are discussed. Resistivity rho(T) of Pr124 shows a nearly metallic behavior similar to what was observed in Pr124 made by the O-2-HIP technique. The metallic rho(T) at low tempe ratures is of interest and will be discussed.