Pressure effects on the structural phase transition in La0.8Ba0.2MnO3 single crystals - art. no. 214417

The magnetic and transport properties, under magnetic field and hydrostatic pressure, of a La0.8Ba0.2MnO3 single crystal are studied. On cooling down, the signatures of the rhombohedral (R) to orthorhombic (O) structural phas e transition at T(S)approximate to 175 K, below the Curie temperature, are clearly signaled by a reduction of the magnetization and some increment of the resistance. It is found that the application of hydrostatic pressure pr oduces a huge downward shift of T-S (dT(S)/dP approximate to - 3 K/kbar) in dicating that the R phase is stabilized under pressure. The magnetic field has a similar effect stabilizing the phase of higher magnetization. i.e., t he R phase (dT(S)/dB approximate to - 0.45 K/T). At the same time, the Curi e temperature T-C approximate to 255 K is shifted to higher temperatures by both magnetic field and pressure (dT(C)/dB approximate to 3 K/T, dT(C)/dP approximate to 1.8 K/kbar). These features are discussed in terms of the re lative energy stability of the R and O phases.