Abstract:Electronic phase separation is one of the most exciting findings during the study of strongly correlated electron systems in past decades. Inhomogeneities at the nanoscale have been proven to not only play a key role in the material properties but also challenge the fundamental concepts of condensed matter physics. In rare earth doped manganites, a nanoscale phase with unique structural modulations has attracted particular attention because of its relationship with the renowned behavior of the material, colossal magnetoresistance (CMR). Direct observations of the nanoscale phases are usually difficult but necessary to unravel the controversies and unveil the underlying physics in this case. In this review paper, recent achievements of direct imaging of the nanoscale phase are shown by using advanced transmission electron microscopic techniques correlated with the material property measurements. Based on those results, the relationship between the nanoscale phase and the CMR effect was established, and unexpected magnetic and physical properties of the nanoscale phase were found. Although the microscopic origin of the nanoscale phase is not fully interpreted yet, the findings here shed light on the pathway to a deeper understanding of the mechanism of CMR and other properties in these materials.
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