March 14, 2016
      
                  
        
  Author(s)
  A. M.  Hallas,    J.  Gaudet,   Nicholas  Butch,    M.  Tachibana,    R. S.  Freitas,    G. M.  Lake,    C. R.  Wiebe,    B. D.  Gaulin
 
       
            
    
    
        The ytterbium pyrochlore magnets, Yb 2B 2O 7 (B=Sn, Ti, Ge) are well described by S eff = 1/2 quantum spins with local XY anisotropy, decorating the cubic pyrochlore lattice and interacting via anisotropic exchange. Structurally, while only the non