Cascade of magnetic field induced spin transitions in LaCoO 3

We present magnetization and magnetostriction studies of LaCoO 3 in magnetic fields approaching 100T. In contrast with expectations from single-ion models, the data reveal two distinct first-order transitions and well-defined magnetization plateaus. The magnetization at the higher plateau is only about half the saturation value expected for spin-1 Co3 + ions. These findings strongly suggest collective behavior induced by interactions between different electronic configurations of Co3 + ions. We propose a model that predicts crystalline spin textures and a cascade of four magnetic phase transitions at high fields, of which the first two account for the experimental data. © 2012 American Physical Society.