Structural reorientation of PLD grown La2NiO4 thin films

Single crystal La2NiO4 films were grown on STO (001) substrates by use of pulsed laser deposition (PLD). It was found that these films grow with the c-axis in the out of plane direction up to a certain critical thickness. Films thicker than that resulted in a structural reorientation from c-axis to a-axis out of plane orientation. The evolution of the c and a axis were measured by using a four circle X-ray diffractometer.