Strain-induced insulator–metal transition and room-temperature colossal magnetoresistance in low-doped La_1-xBa_xMnO₃ thin films

Magnetotransport properties in low-doped La_1-xBa_xMnO₃ thin films were investigated. The bulk La_1-xBa_xMnO₃ (x=0.05 and 0.1) compounds are insulating, but an insulator–metal transition was observed in the strained thin films deposited on SrTiO₃(100) substrates. At x=0.05, magnetization measurements revealed a transition from spin canting in bulk to ferromagnetic order in thin film. Moreover, a large magnetoresistance effect was obtained in the thin film with x=0.1 at room temperature and in a low magnetic field. A strain-induced modification of e_g orbital stability was proposed to explain these properties. © 2001 American Institute of Physics.