We use neutron scattering to study the influence of a magnetic field on spin structures of Nd 2CuO 4. On cooling from room temperature, Nd 2CuO 4 goes through a series of antiferromagnetic (AF) phase transitions with different noncollinear spin structures. While a c-axis aligned magnetic field does not alter the basic zero-field noncollinear spin structures, a field parallel to the CuO 2 plane can transform the noncollinear structure to a collinear one ("spin-flop" transition), induce magnetic disorder along the c axis, and cause hysteresis in the AF phase transitions. By comparing these results directly to the magnetoresistance (MR) measurements of Nd 1.975Ce 0.025CuO 4, which has essentially the same AF structures as Nd 2CuO 4, we find that a magnetic-field-induced spin-flop transition, AF phase hysteresis, and spin c-axis disorder all affect the transport properties of the material. Our results thus provide direct evidence for the existence of a strong spin-charge coupling in electron-doped copper oxides.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2005 Feb|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics