Large lattice distortions associated with the magnetic transition in La0.7Sr0.3MnO3

Abstract

Colossal magnetoresistance (CMR) is associated with the phase transition from a metallic ferromagnetic to insulating paramagnetic phase, which can be controlled by an applied magnetic field. The insulating phase occurs due to trapping of the charge carriers by polaronic lattice distortions, which raise the resistivity. Theories based on local physics predict that the magnitude of the resistivity jump at Tc is determined by how much, on average, the amplitude of these distortions increases at the phase transition. Using neutron scattering, we measured the average distortion amplitude in La0.7Sr0.3MnO3. Surprisingly, its increase from below to above Tc is just as large as in other manganites, which have a much larger resistivity jump. This result suggests that the strength of CMR is determined not by the size of distortions, but by their cooperative nature specific to each compound. Existing theories need to be extended to include correlations between different unit cells to explain and predict the strength of CMR.

References in corpus (2)

• Sliding charge density wave in manganites
• Weak charge-lattice coupling requires reinterpretation of stripes of charge order in La1-xCaxMnO3

Cited by in corpus (7)

• Polaronic metal phases in La${}_{0.7}$Sr${}_{0.3}$MnO${}_3$ uncovered by inelastic neutron and x-ray scattering
• Polaron-mediated spin correlations in metallic and insulating La${}_{1-x}{A}_x$MnO${}_3$ ($A$=Ca, Sr, or Ba)
• Spin wave damping arising from phase coexistence below $T_c$ in colossal magnetoresistive La${}_{0.7}$Ca${}_{0.3}$MnO${}_3$
• Magneto-Dielectric Behavior in $L{a}_{0.53}C{a}_{0.47}Mn{O}_3$
• Damping and softening of transverse acoustic phonons in colossal magnetoresistive La${}_{0.7}$Ca${}_{0.3}$MnO${}_3$ and La${}_{0.7}$Sr${}_{0.3}$MnO${}_3$
• Interacting chains of orbital polarons in "Colossal" magnetoresistive La1-xSrxMnO3 revealed by spin and lattice dynamics
• Polaronic correlations and phonon renormalization in La1-xSrxMnO3 (x = 0.2, 0.3)