Photo-induced variation of electronic transport in La0.7Sr0.3MnO3/SrRuO3 superlattices
Heng-Jui Liu1*, Tzu-Chiao Wei3, Jr-Hau He3, Qing He2, Ying-Hao Chu1
1Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu, Taiwan
2Department of Physics, Durham University, Durham, United Kingdom
3Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, Taiwan
* presenting author:Heng-Jui Liu,
The investigation of complex oxides superlattices has received much interest in the past several decades because of their potential impact for developing novel spintronic devices and coupling-effect-induced intriguing physical phenomena. Here high quality superlattices consisting of strongly correlated oxides manganites (La0.7Sr0.3MnO3, LSMO) and photostrictive (SrRuO3, SRO) have been fabricated using pulsed laser deposition since their electronic properties are very sensitive to crystal symmetry and strain. The structural analysis from X-ray diffraction (XRD) and cross-section transmission electron microscopy (X-TEM) confirms that LSMO and SRO are coherently coupled with each other with presence of periodically alternative arrangement. X-ray magnetic linear dichroism (XMLD) indicates that the orbital moment of LSMO changes its direction on different substrates. Pump-probe measurement also exhibits that SRO has a strong photo-response for its lattice expansion. Therefore, in this work, we propose to use photostrictive SrRuO3 to modulate the strain state of La0.7Ca0.3MnO3 by illuminating the superlattice and further change the direction of orbital degree of freedom or electric transport behavior. Interestingly, the variation of electronic transport behavior has been found to present opposite trend on different substrates while a light is illuminated on the superlattices, where the resistance decreases for the films on STO substrate, and increases on LAO substrates. This results opens up a new control method of operating the spintronic devices through the light illumination.

Keywords: superlattice, LSMO, SRO, transport behavior