Relevance of solid solution randomness for long-range phase separation in highly correlated oxidesC. Frontera and J. L. García-Muñoz
Institut de Ciència de Materials de Barcelona, CSIC, Campus Universitari de Bellaterra E-08193 Bellaterra, Spain, EU
received 22 September 2008; accepted in final form 16 November 2008; published December 2008
published online 12 January 2009
We have studied the role of the intrinsic disorder, introduced by the presence of two different cations at the same crystallographic position, for promoting phase separation in highly correlated oxides. We focus on perovskites with strong phase competition and dilute chemical doping , in which the presence of instead of X is able to produce a local modification of the ground state (for instance, from insulating charge order to ferromagnetic metal). Our results prove that in the dilute case, a low density of cations promoting a local change of state in a volume as small as the first coordination sphere, generates large phase separated regions instead of a diluted distribution of ferromagnetic nanoclusters. Our results demonstrate that diluted chemical disorder can promote phase separation at the microscopic scale in a large variety of oxides with competing states.
71.28.+d - Narrow-band systems; intermediate-valence solids.
71.30.+h - Metal-insulator transitions and other electronic transitions.
75.47.Lx - Manganites.
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