Magnetic field effect on quantum corrections to the low-temperature conductivity in metallic perovskite oxides

The transport and magnetotransport properties of the metallic and ferromagnetic $\mathrm{Sr}\mathrm{Ru}{\mathrm{O}}_3$ (SRO) and the metallic and paramagnetic $\mathrm{La}\mathrm{Ni}{\mathrm{O}}_3$ (LNO) epitaxial thin films have been investigated in fields up to $55\mathrm{T}$ at temperatures down to $1.8\mathrm{K}$. At low temperatures both samples display a well-defined resistivity minimum. We argue that this behavior is due to the increasing relevance of quantum corrections to the conductivity (QCC) as temperature is lowered; this effect being particularly relevant in these oxides due to their short mean free path. However, it is not straightforward to discriminate between contributions of weak localization and renormalization of electron-electron interactions to the QCC through temperature dependence alone. We have taken advantage of the distinct effect of a magnetic field on both mechanisms to demonstrate that in ferromagnetic SRO the weak-localization contribution is suppressed by the large internal field leaving only renormalized electron-electron interactions, whereas in the nonmagnetic LNO thin films the weak-localization term is relevant.

Figure 1

(Color online) Temperature dependence of the resistivity of the SRO (a) and LNO (b) films. Dashed line is the result of the fit using Eq. (2). Insets: zoom of the low-temperature region of resistivity plotted in a semilogarithmic scale.

Figure 2

(Color online) Temperature dependence of the deviation $\Delta {\rho }_n=[{\rho }_{\text{fitting}}\left(T\right)-\rho \left(T\right)]∕\rho \left(T\right)$ corresponding to fittings to expressions (1) (3D limit) and (2) (2D limit) for the SRO (a) and the LNO (b) films.

Figure 3

(Color online) Insets: Resistance versus temperature data measured at zero field as well as at field of $48\mathrm{T}$ for typical SRO (a) and at $9\mathrm{T}$ for LNO (b) films. Main panels: temperature dependence of the resistance measured after subtraction of the resistance at minimum at zero field as well as at field of $48\mathrm{T}$ for SRO (a) and at $9\mathrm{T}$ for LNO (b) films.

Figure 4

(Color online) The field dependence of the magnetoresistance $\mathrm{MR}=[R\left(H\right)-R\left(0\right)]∕R\left(0\right)$ at different temperatures is plotted for the same SRO film as in Fig. 3a $(t=3.5\mathrm{nm})$.

Figure 5

(Color online) (a) The field dependence of the magnetoresistance $\mathrm{MR}=[R\left(H\right)-R\left(0\right)]∕R\left(0\right)$ at different temperatures is plotted for a LNO film with thickness $t=240\mathrm{nm}$. (b) The magnetoconductance change $\Delta \sigma =\sigma \left(H\right)-\sigma \left(0\right)$ is plotted versus $H^{1∕2}$ at different temperatures for the same LNO film. The dashed line through the $2\mathrm{K}$ $\Delta \sigma \left(T\right)$ data is a fitting using Eq. (3). Inset: The $T$ dependence of $\rho$ is fitted to Eq. (5) (dash-dotted line) in the range $5⩽T⩽7.5\mathrm{K}$.

Figure 6

(Color online) The magnetoconductance change $\Delta \sigma =\sigma \left(H\right)-\sigma \left(0\right)$ is plotted versus $H^{1∕2}$ (3D limit) and versus $\ln H$ (2D limit) in the same range of $H$ values for the same LNO film of Fig. 5.