Coexistence of Superconducting and Magnetic Order in CeCoIn$_5$

The interplay between magnetic and superconducting order near a quantum critical point in heavy fermion materials has attracted intensive research interest in recent years. One of the most intriguing examples is that of CeCoIn$_5$, in which a novel phase within the superconducting phase is observed near the critical field at low temperature. Recent nuclear magnetic resonance [1] and neutron scattering [2] experiments showed that a static magnetic order is stabilized in this phase. The microscopic nature of this magnetic state will be discussed.\\[4pt] [1] B.-L. Young \textit{et al.}, Phys. Rev. Lett. \textbf{98}, 036402 (2007).\\[0pt] [2] M. Kenzelmann \textit{et al.}, Science \textbf{321}, 1652(2008).