We present a 139La NMR study on the colossal magneto-resistance (CMR) in double-layered manganese oxide La1.2 Sr1.8 Mn2 O7. Above the Curie temperature TC = 126 K, applying a magnetic field is found to induce a ferromagnetic order that persists up to T = 330 K. The critical field at which the induced magnetic moment is saturated agrees well with the field at which the CMR effect reaches to a maximum. Our results indicate that the CMR observed above TC is due to the field-induced ferromagnetism that produces a metallic state via the double exchange interaction.
- Manganese oxide
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics