[17p-A408-1~14] 6.3 Oxide electronics

[17p-A408-2] Impurity Phase Segregation in a PdCrO₂/CuCrO₂ Heterostructure

〇Tomohiro Ichiba^1,2, Sangmoon Yoon^1,3, Jong Mok Ok^1,4, Mina Yoon¹, Ho-Nyung Lee¹, Fernando Reboredo¹ (1.Oak Ridge Nat. Lab., 2.JAIST, 3.Gachon Univ., 4.Pusan Nat. Lab.)

Keywords:delafossite, density functional theory, ab initio calculation

PdCrO₂ films are synthesized on a CuCrO₂ buffer layer on an Al₂O₃ substrate. This synthesis is accompanied by the segregation of impurity phases, which prevents the synthesis of high-purity PdCrO₂ films. We investigated the cause of the segregation of impurity phases by a combination of experiments and ab initio calculations. X-ray diffraction and scanning transmission electron microscopy experiments revealed the presence of Cu_xPd_1-x alloys and chromium oxides, Cr₂O₃ and Cr₃O₄, on PdCrO₂ as the impurity phases. From the calculations, we found that the lack of oxygen atoms from the stoichiometry (i.e., the release of existing oxygen vacancies and oxygen molecules) is responsible for the segregation of the impurity phases. Therefore, we consider that preventing the release of oxygen from delafossite can suppress the segregation of the impurity phase. In the talk, we will present the results of the experiments and ab initio calculations and explain the above discussion.