Pressure effect on manganites with layered perovskite structure

The colossal magnetoresistance (CMR) observed in several manganese oxides has recently attracted considerable attention from both academic and technological viewpoints. The colossal magnetoresistance materials are compounds based on the ABO3 perovskite structure. The most commonly widely studied family has the chemical formula Re1-xAxMnO3 (where Re is a rare earth such as La or Pr, and A is a divalent alkali such as Sr or Ca), but there is also growing interest in the "Ruddlesden-Popper" series of layered materials Rex+1MnxO3x+1. The layered compounds consist of the double-layered MnO2 planes and the intervening insulating planes stacked along the c-axis. We have been studying the effect of pressure on transport and magnetic properties of Rex+1MnxO3x+1 (x=2). We have shown that the applied hydrostatic pressure suppresses the steep drop of the resistivity of the La1.4Sr1.6Mn2O7 and preserves the two-dimensional charge and spin dynamics down to low temperatures. The pressure will be shown as a powerful tool for studying electronic and magnetic properties of manganites with layered perovskite structure.