High resolution ferromagnetic and antiferromagnetic correlations in La0.7Ca0.3MnO3

La0.7Ca0.3MnO3 (LCMO30) is a perovskite manganite with a phase transition (T-C = 238 K) between a paramagnetic insulator and a ferromagnetic metal. We use single-crystal, inelastic neutron scattering to refine previous work on the low energy (h omega < 10 meV) magnetic excitations. At 300 K the spectrum consists of a diffusive ferromagnetic component at the pseudo-cubic Brillouin zone center coexisting with a quasielastic excitation located at the pseudo-cubic Brillouin zone edge. Both components are anti-correlated with ferromagnetic long-range order, showing weakened intensity at 215 K in the ferromagnetic phase. Polarized neutron scattering shows both features to be purely magnetic in origin. This indicates the simultaneous presence of ferromagnetic and antiferromagnetic correlations (located, respectively, at the zone center and zone edge) in a three-dimensional perovskite, while this coexistence had been previously observed only in a bilayer compound.

Automated summary

This paper investigates the characteristics of low-energy magnetic excitations in the manganese oxide material La0.7Ca0.3MnO3. The results show that at 300K, the magnetic excitations consist of a diffusive ferromagnetic component at the Brillouin zone center and a quasielastic excitation at the Brillouin zone edge, both of which exhibit weakened intensity at 215K.