A measuring method is presented which allows to determine the coniplanar geometric lattice parameters (the amounts of two unit cell vectors and the angle between the both unit cell vectors) of monocrystals with high precision a t one crystal point and in one measurement cycle. The efficiency of the method is demonstrated at measurements of two quartz monocrystals.
Kin Verfahren zur hochprazisen Messung koniplanarer geonietrischer Gitterpararneter, (1. h. der Betrage von zwei Basisvektoren der Elenientarzelle urid des von beideri Basisvektoren eingeschlossenen Winkels, an einem Probenort und in einem MeBtlurchlauf wird vorgestellt. Die Leistungsfahigkeit des Verfahrens wird am Beispiel der Messung von zweiQuarzkristallen demonstriert.
1ntroduct)ionCrystals are increasely used in many fields of science and technology like in microelectronics, optoelectronics, quantumelectronics and scientific instrument production. The majority of the physical properties of crystals is essentially determined by the real structure of the crystals. Therefore the investigation of the real structure is of great scientific and economic importance. The results of this investigation are important preconditions to improve the real structure and thus the physical properties of the crystals.The geometric lattice parameters, these are the amounts of the three unit cell vectors (the so-called lattice constants) and the three angles between the unit cell vectors, are important parameters of the real structure. An absolute determination of one lattice constant with high precision -5 is possible by the BOND method (BOND; BAKER et al.; GROSSWIG et al. (a)). The BOND method is a X-ray diffractometric method which allows an accurat determination of the Bragg angle Ohkl for perfect monocrystals by using a single reflection and by directly measuring the angle between two crystal positions for which the Bragg condition is fulfilled. The interplanar crystal spacing of the reflecting net planes is calculated from the determined Bragg angle by means of the Bragg law and by taking into account the necessary corrections for the peak shift of the reflected intensity distributions. If the crystal symmetry is known then it is possible to calculate a lattice constant from the interplanar crystal spacing. Generally the BOND method allows the determination of an interplanar crystal spacing or a lattice constant respectively a t one point of the sample and in one measuring run only. But in many cases the determination of an interplanar crystal spacing or a lattice constant respectively is insufficient to characterize the real To measure every one of the three lattice constants it is necessary to prepare one extra sample for the measurement of each lattice constant. I n that way it is possible to determine the three lattice constants but each lattice constant is measured on another area of the crystal. This leads to complications in measurements on crystals with local variing lattice constants. The determination of the angles between the unit cell vectors is imposs...
