Direct evidence for charge ordering and electronic phase separation in BixSr1−xMnO3 at room temperature

We present a study of charge ordering and electronic phase separation (EPS) phenomenon in BixSr1−xMnO3, for an exhaustive range of x (0.25⩽x⩽0.75), by STM/STS at room temperature (RT) and specific heat measurements at high temperatures (350-650 K). Atomically resolved STM images of the samples, in real space, show the presence of stripe-like charge-ordered (CO) phase coexisting with charge-disordered (CD) phase. The STM images further reveal that the fraction of CO phase increases with an increase in x. The conductance spectra of these phases measured at nano level by STS are discussed. The transition to CO phase above RT is corroborated by specific heat measurements in all samples, giving a TCO(x) phase diagram for this system.