Composition and field tuned magnetism and superconductivity in   Nd1-xCexCoIn5
  The Nd1-xCexCoIn5 alloys evolve from local moment magnetism (x = 0) to heavy fermion superconductivity (x =1). Magnetic order is observed over a broad range of x. For a substantial range of x (0.83 <= x <= 0.95) in the temperature - composition phase diagram we find that superconductivity may coexist with spin - density wave magnetic order at the Fermi surface. We show that a delicate balance betwen superconducting and magnetic instabilities can be reversibly tuned by both the Ce/Nd ratio and magnetic field, offering a new and unique model electronic system. 
Rongwei Hu, Y. Lee, J. Hudis, V. F. Mitrovic, and C. Petrovic