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 phase 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 produces a huge downward shift of T-S (dT(S)/dP approximate to - 3 K/kbar) indicating that the R phase is stabilized under pressure. The magnetic field has a similar effect stabilizing the phase of higher magnetization. i.e., the R phase (dT(S)/dB approximate to - 0.45 K/T). At the same time, the Curie 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 relative energy stability of the R and O phases.