TY - JOUR
T1 - Tip Induced Surface Defect migration and Conductivity Studies in Tetragonal, Rhombohedral and Mixed-Phase epitaxial BiFeO3 Thin Films
AU - Mohandas Moolayil, Saj Mohan
AU - Sreenath, M.V.
AU - Ramadurai, R.
PY - 2018
Y1 - 2018
N2 - BiFeO3 (BFO) is the most studied room temperature multiferroic compound. In this work we demonstrate a template assisted growth process through which the growth strain is controlled to achieve required phase of BFO. Growth of (∼20nm) fully strained tetragonal (T), rhombohedral (R) and mixed phase of T and R of Bismuth ferrite (BiFeO3) was achieved by varying the thickness of the template layer. The different phases were confirmed by using high resolution x-ray diffractions studies. The conductivity map of all the three phases were carried out using an atomic force microscope operating in conductive mode. Tip induced surface defect migration within a given grain was observed in pure phases and the conductivity map confirmed the same. The room temperature resistivity is found to be decreasing systematically from 1.1×10^6 Ωm , 935×10^5 Ωm and 1.16×10^4 Ωm respectively for tetragonal, mixed phase and rhombohedral phase BFO. In the case of mixed phase both the nano- scale and macroscopic leakage current studies show low conductivity, which could be due to the increased pinning sites that increases the energy barrier for the defect migration. The local nano-scale measurements and conductivity mapping corroborates well with the macroscopic studies.
AB - BiFeO3 (BFO) is the most studied room temperature multiferroic compound. In this work we demonstrate a template assisted growth process through which the growth strain is controlled to achieve required phase of BFO. Growth of (∼20nm) fully strained tetragonal (T), rhombohedral (R) and mixed phase of T and R of Bismuth ferrite (BiFeO3) was achieved by varying the thickness of the template layer. The different phases were confirmed by using high resolution x-ray diffractions studies. The conductivity map of all the three phases were carried out using an atomic force microscope operating in conductive mode. Tip induced surface defect migration within a given grain was observed in pure phases and the conductivity map confirmed the same. The room temperature resistivity is found to be decreasing systematically from 1.1×10^6 Ωm , 935×10^5 Ωm and 1.16×10^4 Ωm respectively for tetragonal, mixed phase and rhombohedral phase BFO. In the case of mixed phase both the nano- scale and macroscopic leakage current studies show low conductivity, which could be due to the increased pinning sites that increases the energy barrier for the defect migration. The local nano-scale measurements and conductivity mapping corroborates well with the macroscopic studies.
U2 - 10.1557/adv.2018.463
DO - 10.1557/adv.2018.463
M3 - Article
SN - 2059-8521
VL - 3
SP - 2713
EP - 2718
JO - MRS Advances
JF - MRS Advances
ER -