Synchrotron Topographic Studies of Domain Structure in Czochralski Grown $Pr_xLa_{1-x}AlO_3$ and $Pr_xLa_{1-x-y}Mg_yAlO_3$ Crystals

A domain structure and crystallographic defects in Czochralski grown single crystals of $Pr_xLa_{1-x}AlO_3$ and $Pr_xLa_{1-x-y}Mg_yAlO_3$ were characterised with a number of methods including conventional and synchrotron X-ray diffraction topography, and polariscopic micrography. The observed twin domain systems were located perpendicularly to 〈100〉$\text{}_\text{pcub}$ and 〈110〉$\text{}_\text{pcub} (pseudocubic) directions. It has been confirmed that the domains are of the same orientation and a twin character as those described in literature for $LaAlO_3$ and $LaGaO_3$ crystals. The use of section transmission topography enabled to indicate that the domains are perpendicular to the $(100)_\text{pcub}$ surface of the samples. The misorientation of lattice in the domains was evaluated from the white beam topographs and a tendency of its increase with increasing concentration of praseodymium was revealed.