Growth of EuO single crystals at reduced temperatures
  Single crystals of (Eu$_{1-x}$Ba$_x$)O have been grown in a molten barium-magnesium metal flux at temperatures up to 1000{\deg}C, producing single crystals of (Eu$_{1-x}$Ba$_x$)O with barium doping levels ranging from $x=0.03$ to $x=0.25$. Magnetic measurements show that the ferromagnetic Curie temperature T$_C$ correlates with the Ba doping levels, and a modified Heisenberg model was used to describe the stoichiometry dependence of T$_C$. Extrapolation of the results indicates that a sample with Ba concentration of $x=0.72$ should have a T$_C$ of 0 K, potentially producing a quantum phase transition in this material. 
Daniel C. Ramirez, Tiglet Besara, Jeffrey B. Whalen, Theo Siegrist
cond-mat.mtrl-sci