title: Anomalous magnetoresistance in the spinel superconductor LiTi2O4.
abstract: LiTi2O4 is a unique compound in that it is the only known spinel oxide superconductor. The lack of high quality single crystals has thus far prevented systematic investigations of its transport properties. Here we report a careful study of transport and tunnelling spectroscopy in epitaxial LiTi2O4 thin films. An unusual magnetoresistance is observed which changes from nearly isotropic negative to prominently anisotropic positive as the temperature is decreased. We present evidence that shows that the negative magnetoresistance likely stems from the suppression of local spin fluctuations or spin-orbit scattering centres. The positive magnetoresistance suggests the presence of an orbital-related state, also supported by the fact that the superconducting energy gap decreases as a quadratic function of magnetic field. These observations indicate that the spin-orbital fluctuations play an important role in LiTi2O4 in a manner similar to high-temperature superconductors.
authors.affiliation: 1] Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China [2] Collaborative Innovation Center of Quantum Matter, Beijing 100190, China [3] Center for Nanophysics and Advanced Materials and Department of Physics, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: K
authors.initials: K
authors.lastname: Jin
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: G
authors.initials: G
authors.lastname: He
authors.affiliation: 1] Center for Nanophysics and Advanced Materials and Department of Physics, University of Maryland, College Park, Maryland 20742, USA [2] Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: X
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: S
authors.initials: S
authors.lastname: Maruyama
authors.affiliation: Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: S
authors.initials: S
authors.lastname: Yasui
authors.affiliation: Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: R
authors.initials: R
authors.lastname: Suchoski
authors.affiliation: Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: J
authors.initials: J
authors.lastname: Shin
authors.affiliation: Center for Nanophysics and Advanced Materials and Department of Physics, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: H S
authors.initials: HS
authors.lastname: Yu
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: J
authors.initials: J
authors.lastname: Yuan
authors.affiliation: 1] Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China [2] Collaborative Innovation Center of Quantum Matter, Beijing 100190, China.
authors.forename: L
authors.initials: L
authors.lastname: Shan
authors.affiliation: Department of Physics, Loughborough University, Loughborough LE11 3TU, UK.
authors.forename: F V
authors.initials: FV
authors.lastname: Kusmartsev
authors.affiliation: Center for Nanophysics and Advanced Materials and Department of Physics, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: R L
authors.initials: RL
authors.lastname: Greene
authors.affiliation: Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: I
authors.initials: I
authors.lastname: Takeuchi