Growth and Properties of $a$-Axis Oriented Thin Films of Infinite-Layer $\hbox{Sr}_{1 - x}\hbox{La}_{x} \hbox{CuO}_{2}$

A
-axis oriented, electron-doped, Sr
_1-x
La
_x
CuO
₂
thin films were grown on LaAlO
₃
and YAlO
₃
substrates by magnetron sputtering. X-ray diffraction analysis revealed that in an as-grown state, the
a
-axis oriented films grew with the long-
c
phase, which is related to oxygen vacancies in the CuO
₂
planes, unlike the
c
-axis oriented films. Another feature of our
a
-axis oriented films is that the films contain 90
^°
rotated domains from in-plane X-ray diffraction and planer transmission electron microscopy image. We discuss features of
a
-axis oriented films in terms of oxygen vacancies in the CuO
₂
planes.