Effect of Li+ codoping on the mechanical strength of YB:ZnWO4 single crystals

• Yb3+ segregation coefficient in ZnWO4 doubles when Li+ is added into the crystal composition. • Li+ segregation coefficient in ZnWO4 is practically independent on its content in the crystal. • Yb3+ and Li+ concentrations in Yb,Li:ZnWO4 were optimized providing the best crystal strength. ZnWO 4 single crystals both undoped and doped with various concentrations of Yb 3+ and Li + ions have been grown. The actual concentrations of dopants had been measured by atomic emission spectroscopy with inductively coupled plasma, as well as by polarized optical absorption spectroscopy. The segregation coefficients of the dopants between the crystal and melt have been evaluated. Hardness and fracture toughness of the crystals were measured by indentation method. The dependencies of the measured values on the dopants concentrations were analyzed. The optimal dopants concentrations, providing the best mechanical strength of Yb,Li:ZnWO 4 crystal have been found.