Abstract
Neutron and x-ray diffraction studies show that the simultaneous first-order transition to an orthorhombic and antiferromagnetic (AFM) ordered state in splits into two transitions with Co doping. For , a tetragonal-orthorhombic transition occurs at , followed by a second-order transition to AFM order at . Superconductivity occurs in the orthorhombic state below and coexists with AFM. Below , the static Fe moment is reduced along with a redistribution of low energy magnetic excitations indicating competition between coexisting superconductivity and AFM order.
- Received 16 March 2009
DOI:https://doi.org/10.1103/PhysRevLett.103.087001
©2009 American Physical Society