Abstract and subjects
We have studied the magnetic order inside the superconducting phase of CeCoIn5 for fields along the 1/2100 crystallographic direction using neutron diffraction. We find a spin density wave order with an incommensurate modulation Q 1/4 ðq; q; 1=2Þ and q 1/4 0:45ð1Þ which within our experimental uncertainty is indistinguishable from the spin density wave found for fields applied along 1/21 1 0. The magnetic order is thus modulated along the lines of nodes of the dx2 y2 superconducting order parameter suggesting that it is driven by the electron nesting along the superconducting line nodes. We postulate that the onset of magnetic order leads to reconstruction of the superconducting gap function and a magnetically induced pair density wave.