Magnetic and EPR Studies of Oxygenated and Non‐Oxygenated LaBaSrCu 3 O 6+ x Compounds in the Tetragonal Phase

Oxygenated and non‐oxygenated LaBaSrCu 3 O 6+x ceramics in the tetragonal phase are studied using X‐ray, EPR, and magnetic measurements. A Meissner signal for the oxygenated sample corresponding to almost perfect diamagnetism is measured below 35 K. However, EPR data indicate that at least some parts of the sample become superconducting already below 62 K. Magnetic susceptibility of the non‐oxygenated sample exhibit a significant paramagnetic contribution attributed to Cu(1) ions ferromagneticall coupled to the Cu(2) planes.