LiTi2O4 (LTO) has attracted much attention as it is the only known oxide superconductor with the spinel structure and it has a relatively high bulk superconducting transition temperature (Tc) of 11K [1].

However, the development of an understanding of this system has been hampered by the lack of sample reproducibility and the availability of single crystals or high quality thin films. A few years ago, high quality epitaxial LTO thin films were successfully grown by pulsed laser deposition thus opening the door for systematic experiments on LTO [2].

In this talk, I will present results of transport and tunneling studies on single crystalline-like epitaxial LTO thin films. In the normal state, the Hall coefficient shows a nearly constant value with a positive sign over a broad temperature range, suggesting a single-band hole-like electronic transport. The magnetoresistance of the material shows an unexpected change in the sign at 50 K. Below this temperature, the resistance shows a conventional parabolic increase with field. However, above this temperature, an unusual negative magnetoresistance appears. In the superconducting state, an upper critical field of about 18 Tesla is found by both magnetotransport and point-contact tunneling spectroscopy (PCS). In addition, our PCS results suggest that the superconducting gap in LTO is BCS-like. A possible cause of the unusual negative magnetoresistance will be discussed. And results on the field effect using ionic liquid gating will also be presented.