VALENCY CONTROL OF IRON IN Y3FE5O12 SINGLE-CRYSTALS GROWN BY THE FLOATING-ZONE METHOD

Doping of Y3Fe5O12 (YIG) single crystals with various elements, such as Si, Ca, Mg, Mn, Mo, and V, has shown that Mn is the most appropriate dopant for improving the transparency in the near infrared. Mn doping does not show any additional absorption (wavelength range 0.8 to 2 mu m), and results in YIG crystals with very high transparency. By determination and optimization the ratio of the C-s/C-f (C-s dopant concentration in the flux rod; C-f: that in the feed rod) as a function of the distribution coefficient k, even when the k value is not unity, YIG crystals were grown by the floating zone method with the variation of transparency along the growth direction exceedingly small.