THE INFLUENCE OF MAGNETIC-FIELD AND PRESSURE ON THE STRUCTURAL PHASE-TRANSITION IN LA1-XSRXMNO3

Neutron diffraction techniques have been used to investigate the influ ence of applied magnetic field and pressure on the structural and magn etic phase transitions in La1-xSrxMnO3. The structural, magnetic and e lectronic properties are found to be strongly coupled. For suitable co mpositions the coupling between the magnetism and the crystal structur e becomes so strong that the structural phase transition may be driven by the application of a magnetic field. The influence of pressure on both the structural and ferromagnetic phase transition is summarized i n a pressure-temperature phase diagram. This diagram reveals several u nusual features, including the pressure independence of the Curie poin t in the orthorhombic phase, a re-entrance of the rhombohedral phase a t low temperatures, and a change of order of the magnetic phase transi tion.