The crystal growing tradition

Met Zach Fisk at a workshop - interesting, considering we've all descended from him. A couple of his off-the-cuff remarks were that fluxes he uses are sometimes binary: eg. to grow YbxCuyInz, he might use a Cu:In flux rather than just In as I would have guessed. Also, at one point I had considered using BeO crucibles instead of Al2O3 - I didn't actually end up doing this, but if one ever does, apparently BeO sucks up large quantities of water very quickly, and needs to be dried out before use each time. But apparently Zach Fisk's greatest asset is that he is very good at telling dinner party stories :)

Crucibles

This is a really basic qn. for Oxide crystal growers... How do we decide when to use Al crucibles sealed in Quartz or Pt crucibles? Si obviously attacks quartz - but how about the the other oxides we've grown, why do we use Pt?

Furnace E calibration

Last week I put identical ErTe3 growths in Furnace C and Furnace E, two in each furnace; both were spun at 515 C. The growths in Furnace C spun clean, whereas half of the contents of each Furnace E growth was encased in a tellurium lump.

RTe3 growers: Have you observed this tellurium lump phenomenon and have you thought about how to avoid it? My thought is that this occurs when the spin temperature is too low, and too close to the tellurium melting point.

My hypothesis is that Furnace E is calibrated so that 515 C is lower than it is in Furnace C. For this week's ErTe3 growths, I will spin Furnace E at 520 C and Furnace C at 515 C.

Any comments?