Slight Ti‐Doping‐Induced Strong Time‐Dependent Electrical Transport Behavior in CuCr_1−xTi_xO₂

Abstract

We investigate the effect of slight Ti substitution (≤0.5%) for Cr in CuCr1−xTixO2 by measuring the structural, magnetic, and electrical transport properties. Upon Ti doping, the antiferromagnetic transition becomes blurred without a change in Néel temperature. Ti4+ substituting to Cr3+ site is found to significantly enhance the resistivity due to the diminishing conducting holes. We find strong time‐dependent electrical transport behavior in CuCr1−xTixO2 induced by slight Ti doping. The key observation is that a metastable behavior occurs in Ti‐doped CuCr1−xTixO2. A strong resistive relaxation (RR) behavior occurs in Ti‐doped CuCr1−xTixO2 with its magnitude remarkably increasing with increasing Ti content, while it is absent in undoped CuCrO2. The RR is found to be described by the combination of an exponential function and a logarithmic dependence at long time. The relaxation behavior in CuCr1−xTixO2 is found to show a correlation with the local lattice deformation.

Local crystal structure and physical properties change of p-type transparent conducting oxide: CuCrO2 upon Ti-substitution

“…Another study reports the crystal and magnetic properties of Ti substitution at the Cr 3þ site, 18 claiming Ti to adopt a 2þ state, whereas Li et al reports a strong resistive relaxation behavior in CuCr 1-x Ti x O 2 and argues that it is Ti 4þ that substitutes the Cr 3þ site, leading to a significant increase in the resistivity due to the diminishing conducting holes. 19 Hence, it becomes pertinent to re-visit such a study and clarify the valence state and its impact on the interesting properties of this important delafossite composition.…”