Figure 4: Magnetoresistivity and susceptibility features of LiTi₂O₄ thin films.

(a) Temperature-dependent longitudinal magnetoresistivity (B//ab plane//I), Δρ_xx=ρ_xx(B)−ρ_xx(0T), is replotted to demonstrate the crossover temperature (also see Fig. 3b). (b) dρ_xx/dT in zero field. It deviates from the Fermi liquid behaviour, dρ_xx/dT∼T (grey line), at lower temperatures. (c) Twofold symmetry of in-plane (ab plane) resistivity, where ρ_max (θ=90°) and ρ_min (θ=0°) are found from plots such as indicated in the inset. The inset shows a typical twofold symmetry at 30 K and 9 T against θ, which is the angle between the normal direction to current and the field. The error bars are maximum data noise as seen in the inset. (d) The susceptibility with field cooling (1,000 Oe, B//ab plane) shows a Curie–Weiss behaviour at high temperature (see inset χ⁻¹(T)). We plot the residual susceptibility δχ as a function of temperature after subtracting the paramagnetic contribution. The δχ starts to increase below 100±10 K, coincident with the starting temperature of the twofold symmetry of in-plane resistivity. (e) The susceptibility with zero-field cooling shows a good superconducting screening signal, suggesting our LTO films are of high quality. The shading areas around 100 K and 50 K represent the uncertainties in defining the starting point of the anisotropic AMR and the abrupt increase, respectively.