Charge localization in Co doped Ceria with oxygen vacancies

G. E. MURGIDA; A. M. LLOIS; V. FERRARI; V. VILDOSOLA

Buenos Aires, Argentina

Congreso; At the Frontiers of Condensed Matter V; 2010

The search and development of novel materials, fer-romagnetic beyond room temperature, is currently asubject of intense work with the driving force of itspotential technologicalapplications. In this regard,Cerium oxide with diluted magnetic impurities is anatural candidate for spintronics as it offers a goodintegrability with the current electronic devices. How-ever, this material still poses several questions beingthe main one to find a widely acceptable explanationfor the observed room temperature ferromagnetism.There is experimental evidence supporting the ideathat the free electrons left behind by oxygen vacan-cies localize themselves in specific Cobalt and Ceriumatoms, changing their oxidation states (Co4+ → Co2+and Ce4+ → Ce3+ , respectively) and turning theCerium atoms into magnetic ones. The study of thischarge localization is crucial to approach an under-standing of the magnetic properties in these materials.Using the framework of the density functional theory,we study the relative stability of different Oxygen va-cancies and we show that they tend to locate close tothe Co impurities. In addition, we address the issueof charge localization in these materials for differentconcentrations of both Co impurities and Oxygen va-cancies.