Growth of Compounds with Volatile Constituents

Most SrTi03 crystals have been grown by flame-fusion methods where initially the overflow problem was observed after growth of the initial crystal cone, even when excess SrO was added to the starting powder. This phenomenon is explained by the SrO - Ti02 phase diagram shown in Fig. 16.19 overflow is expected both for shortage and for excess of SrO. 

The exact compensation of the evaporated species (SrO) as a function of the growth rate has to be estabhshed in the starting powder, as was shown in the masters thesis of Bednorz [2] who later received together with K.A. Mueller the Nobel Prize for physics for stimulating the discovery of high-temperature superconductivity above liquid-nitrogen temperature. The relation of growth rate 

This was confirmed by Nassau [27] who grew SrTi03 crystals at 4% excess SrCOj and a growth rate of 10 mm h .  

Education of crystal growth engineers will help in establishing this optimum technology and will reduce the multiyear training required to become a flame-fusion crystal grower. 

Elwell, H.J. Scheel, 1975, Crystal Growth from High-Temperature Solutions, Academic Press, 

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