Strong correlation effects and new phase transition at high pressure–low temperature in La0.5Ba0.5FeO3

The physical properties of La0.5Ba0.5FeO3 perovskite have been investigated. The resistivity and magnetism change at around the charge disproportionation temperature. The ferromagnetic cluster-glass state appears when T<115K. Under 5 kbar pressure a new phase transition at 5.5 K is found in the magnetization measurement. The transition temperature increases with the increase of the applied pressure. It is suggested that this transition is induced by the spin state transition from Fe3+(t2g3↑eg2↑) to Fe3+(t2g3↑t2g2↓) with the pressure increase.