Pressure-induced insulating state in (La,Sr)CoO3 -: art. no. 140403

We have investigated the effect of pressure on the electronic, magnetic, and structural properties on a single crystal of conducting, ferromagnet (T-C=157 K) La0.82Sr0.18CoO3 located near the boundary of the metal-insulator transition. Contrary to the results reported on related systems, we find a transition from the conducting state to an insulating state and a decrease of T-C with increasing pressure while the lattice structure remains unchanged. We show that this unusual behavior is driven by a gradual change of the spin state of Co3+ ions from magnetic intermediate-spin (t(2g)(5)e(g)(1);S=1) to a nonmagnetic low-spin (t(2g)(6)e(g)(0);S=0) state.