Control of Fermi Level by Variation of Charge Ordering State in Yb_1-xTi_xFe₂O₄

Abstract

Fermi level and valence state were investigated in RFe₂O₄ (R = Y, Dy, Ho, Er, Tm, Yb, Lu, Sc, or In), which shows magnetoelectric effect originating from charge and magnetic orders of Fe²⁺ and Fe³⁺. We succeeded in controlling the Fermi level of YbFe₂O₄ system by Ti⁴⁺ substitution for Yb³⁺. The variation in the ratio of Fe²⁺ to Fe³⁺ is suggested to the origin of the Fermi level variation. This report suggests the possibility of simple selection of conduction type in functional oxide.