Single-crystal neutron-diffraction study of a structural phase transitioninduced by a magnetic field in ${\mathrm{La}}_{1\mathrm{-}\mathrm{x}}$${\mathrm{Sr}}_{\mathrm{x}}$${\mathrm{MnO}}_3$

The compound ${\mathrm{La}}_{1\mathrm{-}\mathrm{x}}$ ${\mathrm{Sr}}_{\mathrm{x}}$ ${\mathrm{MnO}}_3$ undergoes structural and magnetic phase transitions as a function of temperature and pressure. The temperature at which the structural phase transition from a high-temperature rhombohedral phase to a low-temperature orthorhombic phase takes place is very sensitive to the level of doping (x) and pressure, the magnetic transition temperature to a ferromagnetically ordered state less so. Recent magnetostriction and resistivity measurements have suggested that the structural transition may also be driven by the application of a magnetic field. We have performed single-crystal neutron-diffraction experiments which confirm that by carefully controlling the level of doping the structural phase transition can be induced at constant temperature by application of a magnetic field.