Jahn–Teller distortion and cluster-glass like behavior in La 0.875Ca 0.125MnO 3

Abstract

Neutron diffraction and magnetization measurements were carried out on both powder and single crystal samples of La 0.875Ca 0.125MnO 3. At room temperature (RT), this sample is paramagnetic and single phase, with crystallographic symmetry Pnma (the longest axis is b-axis). Neutron powder diffraction shows that the average magnetic moment of Mn ions is 3.0 (1) μ B/Mn at 10 K, which is significantly less than an averaged moment estimated from the ratio of Mn 3+/Mn 4+ which amounts to 3.875 μ B for 12.5% Mn 4+, an indication of spin canting. The crystal structure is characterized by the ordering of two e g orbitals, being evidenced by the anomalous change of Mn–O bond lengths which starts from 100 K with decreasing temperature. Neutron diffraction measurement was carried out at 8 K and RT. Diffuse scattering at around 1/2 0 1/2 point was observed at 8 K but disappeared in the paramagnetic region.