The 100 nm thick LCMO thin films were deposited on miscut LSAO substrates with [(001).sub.LSAO] plane tilted to the surface Wafer at an angle a of 10[degrees] by facing-target sputtering technique from stoichiometry targets .
For the photovoltaic measurements, two Ag electrodes (1 x 5 [mm.sup.2] in size) separated by 3 mm were prepared on the surface of the LCMO, as shown in Figure 2(b).
Except for the (00/) LSAO substrate and the (h0h) LCMO film reflections, there was no diffraction peak from impurity phase or randomly oriented grain, indicating the epitaxial growth of the sample.
The linear current-voltage (I-V) characteristics, shown in Figure 2(a), of the LCMO films indicated ohmic contacts between the films and Ag electrodes.
The ultrafast laser pulses irradiated the LCMO film surface uniformly and generated photoinduced charge carriers (electron and hole pairs) with gradient distribution ([dn.sub.i]/dz) perpendicular to the film surface .
These experimental results show that the photoinduced voltage effect in the tilting LCMO films is not only an ultrafast process but also highly sensitive to the UV laser pulse.
Thus, LCMO deposited on MgO substrates with large lattice mismatch shows higher photovoltaic sensitivity.