Chemical and microscopical investigations on Ti‐ and Mg‐doped LiNbO₃ single crystals

Abstract

I n lithium niobate single crystals grown by the Czochralski-technique from Mg-and Tidoped melts the concentration distributions of the dopants and the iiiicroinhoniogeneities were investigated using chemical analysis, optical microscopy and scanning electron microscopy in connection with (energy dispersive) X-ray microanalysis. It was found that Mg dopants, if present in the melt simultaneously with Ti, increase the effective distribution coefficient of the titariiuiii dopants. This results in a higher quality of the crystals because of a probably improved stability of the crystallization front.An Lithiuniniobat-Einkristtllen, die nach dem Czochralski-Verfahren aus Mg-und Tidotierten Schnielzeri geziichtet waren, wurden die Konzentrationsverteilungen der Zusatze und die Mikroinhomogenitaten riiittels cheinischer Analyse, optischer Mikroskopie imd Rasterelektronenmikroskopie in Verbindung rnit (energiedispersiver) Rontgenmikroanalyse untersncht. I m Fall der gleichzeitigen Anwesenheit heider Zusatze in der Schmelze wurde gefunden, daB die Mg-Dotierungen den effektiven Verteilungskoeffizientcli der TiZusatze erhohen. Daraus resultiert eine verbesserte Kristallqualitlit, wahrscheirilich als Folge gr6Berer Stabilitat der Kristallisationsfront.

Ti3+on Nb site: A paramagnetic Jahn-Teller center in vacuum-reducedLiNbO3Corradi1, Zaritskii2, Hofstaetter3 et al. 1998Phys. Rev. B260120View full textAdd to dashboardCite

“…The portion of dopants incorporated into the crystals has been investigated by atomic absorption analysis. 11 The distribution coefficient for single doping with Ti was found, in accordance with previous results, 12 to be somewhat smaller than 1, however, the presence of the Mg codopant was seen to increase the built-in amount of Ti by roughly 100%. 11 The concentration of Ti in the double-doped samples used has been estimated to be 0.06Ϯ0.02 mol %.…”

“…11 The distribution coefficient for single doping with Ti was found, in accordance with previous results, 12 to be somewhat smaller than 1, however, the presence of the Mg codopant was seen to increase the built-in amount of Ti by roughly 100%. 11 The concentration of Ti in the double-doped samples used has been estimated to be 0.06Ϯ0.02 mol %. Samples of typically 2ϫ3 ϫ8 mm 3 size were reduced by annealing during one hour at 920°C in a vacuum of 5ϫ10 Ϫ5 torr, with subsequent slow cooling to room temperature.…”

Electron microscopic investigations on optical oxide single crystal

“…Comparing the EDS spectra registered on reference crystal places and at recognizible inclusions, the following foreign elements as possible dangerous ones, could be selected (MALICSK~ et al 1982(MALICSK~ et al , 1984(MALICSK~ et al , 1985MALICSK~ 1987): Pt, Mg, Al, Si, K, Cu, Ti -for LN; Pt, Fe, Al, Si, K, Te -for BGO; and Pt, Al, Si, S, Mg, K, Fe -for TDO. According to the SAD analyses the foreign particles were mainly different oxydes of these elements.…”