Abstract
We use neutron scattering to study the influence of a magnetic field on spin structures of . On cooling from room temperature, goes through a series of antiferromagnetic (AF) phase transitions with different noncollinear spin structures. While a -axis aligned magnetic field does not alter the basic zero-field noncollinear spin structures, a field parallel to the plane can transform the noncollinear structure to a collinear one (“spin-flop” transition), induce magnetic disorder along the axis, and cause hysteresis in the AF phase transitions. By comparing these results directly to the magnetoresistance (MR) measurements of , which has essentially the same AF structures as , we find that a magnetic-field-induced spin-flop transition, AF phase hysteresis, and spin -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.
5 More- Received 2 September 2004
DOI:https://doi.org/10.1103/PhysRevB.71.054505
©2005 American Physical Society