Small-polaron hopping conductivity in bilayer manganite La${}_{1.2}$Sr${}_{1.8}$Mn${}_2$O${}_7$

Abstract

We report anisotropic resistivity measurements on a La${}_{1.2}$Sr${}_{1.8}$Mn${}_2$O${}_7$ single crystal over a temperature $T$ range from 2 to 400 K and in magnetic fields $H$ up to 14 T. For $T\ge 218$ K, the temperature dependence of the zero-field in-plane ${\rho }_{ab}(T)$ resistivity obeys the adiabatic small polaron hopping mechanism, while the out-of-plane ${\rho }_c(T)$ resistivity can be ascribed by an Arrhenius law with the same activation energy. Considering the magnetic character of the polarons and the close correlation between the resistivity and magnetization, we developed a model which allows the determination of ${\rho }_{ab,c}(H,T)$. The excellent agreement of the calculations with the measurements indicates that small polarons play an essential role in the electrical transport properties in the paramagnetic phase of bilayer manganites.

4 pages, 3 figures, to appear in Physical Review B

References in corpus (2)

• Charge melting and polaron collapse in $L{a}_{1.2}S{r}_{1.8}M{n}_2{O}_7$
• Low-temperature electrical transport in bilayer manganite La${}_{1.2}$Sr${}_{1.8}$Mn${}_2$O${}_7$

Cited by in corpus (5)

• Variable-range-hopping conductivity of half-doped bilayer manganite LaSr${}_2$Mn${}_2$O${}_7$
• Polaronic metal phases in La${}_{0.7}$Sr${}_{0.3}$MnO${}_3$ uncovered by inelastic neutron and x-ray scattering
• Large lattice distortions associated with the magnetic transition in La0.7Sr0.3MnO3
• Polaronic correlations and phonon renormalization in La1-xSrxMnO3 (x = 0.2, 0.3)
• Coherence of polaronic transport in layered metals