Complex magnetic ordering in CeGe1.76 studied by neutron diffraction

Neutron diffraction measurements on a single crystal of CeGe1.76 reveal a complex series of magnetic transitions at low temperature. At TN≈7 K, there is a transition from a paramagnetic state at higher temperature to an incommensurate magnetic structure characterized by a magnetic propagation vector (0 0 τ) with τ≈14 and the magnetic moment along the a axis of the orthorhombic unit cell. Below TLI≈5 K, the magnetic structure locks in to a commensurate structure with τ=14 and the magnetic moment remains along the a axis. Below T4 K, we find additional half-integer and integer indexed magnetic Bragg peaks consistent with a second commensurately ordered antiferromagnetic state.