The effects of lithium isotopic anomalies on lithium niobate

Abstract

The effects of variations in the isotopic ratios of lithium are discussed in light of their impact on critical compositions of lithium niobate. Such variations have been observed in naturally occurring as well as refined materials and can alter the atomic weight of lithium in these materials from the natural average of 6.9409 to as high as 7.015 or as low as 6.923. A recently conducted survey of lithium niobates that originated from a single supplier showed inconsistent atomic weights for lithium with an upper limit of 6.963. Lithium niobate crystals grown using weighed components with such uncontrolled compositions can be expected to have an inherent compositional error of 0.05 mole% Li2O. Precise control of composition is vital in the growth of uniform crystals for integrated optic devices. Also, the vulnerability of electro-optic devices made from lithium compounds to radiation damage by neutrons can be improved 99.9% using readily available materials depleted in 6Li.