用富钇法克服大尺寸Nd^(3+)∶YAlO_3晶体的云层

Prevention of Cloudiness in Large-Size Nd^(3+):YAIO_3 Crystals by Surplus Yttrium

Nd_(3+)∶YAIO_3晶体中的云层是由于融体富铝而产生的。YAIO_3晶体用料 Y_2O_3中有值得注意的碳杂质。在高温和缺氧条件下,这些碳杂质与 Al_2O_3或刚玉容器的反应产物,不纯的碳化铝(Al_4C_5·Al_2O_3)是引发晶体光弥散点(<1μm)和云层的有害杂质。在除碳后 Y_2O_3中有小于0.02wt-%的碳和大于0.03wt-%的铝;当 Y_2O_3中的铝等于0.05wt-%(即用重量法按组成式 Nd_(?)Y_1-(?)AlO_3称量的熔料富铝0.3at.%)时,得到有云层的晶体。用称量式 Nd_(?)Y_(1-(?))+ΔxAlO_3(x=0.01,0.003<Δx<0.02)称量的富钇熔料能够生长出无云层和无光弥散的大尺寸 Nd^(3+)∶YAlO_3单晶。

The cloudiness in Nd^(3+):YAlO_3 crystals arises from the melt of surplus Alumi-nium.There are considerable carbon impurities in Y_2O_3 used as one of the materials forYAlO_3 crystal growth.Under the condition of high temperature and lacking of oxygen,thereactants of the carbon impurities with Al_2O_3 (or a corundum container) as well as theimpure aluminium carbide (such as Al_4C_3·Al_2O_3) are the harmful impurities which give riseto light-scattering particles (<1μm) and cloudiness in YAlO_3 crystals during the crystalgrowth.There exist C of less than 0.02wt-% and Al of more than 0.03wt-% in Y_2O_3after carbon being removed.When Al in the Y_2O_3 equals to 0.05wt-%,i.e.The raw ma-terials have surplus aluminium of 0.3at.% in accordance with constituent formula Nd_xY_(1-x)AlO_3 by the weight,the cloudiness occurrs obtained in the crystals.It is successfully provedthat large-size Nd^(3+):YAlO_3 crystals without cloudiness and light-scattering particles can be grown from the melt of surplus yttrium weighed in accordance with weighing formulaNd_xY_(1-z+Δx)AlO_3 (where x=0.01,0.003<Δx<0.02).