arXiv subjects

Wanli Zhang

Publications and source records attributed to Wanli Zhang.

22 records · Page 2Linked to original sources

arXiv2012

Substrate effect on the resistive switching in BiFeO3 thin films

BiFeO3 thin films have been deposited on Pt/sapphire and Pt/Ti/SiO2/Si substrates with pulsed laser deposition using the same growth conditions, respectively. Au was sputtered as the top electrode. The microscopic structure of the thin film varies by changing the underlying substrate. Thin films on Pt/sapphire are not resistively switchable due to the formation of Schottky contacts at both the top and the bottom interface. However, thin films on Pt/Ti/SiO2/Si exhibit an obvious resistive switching behavior under forward bias. The conduction mechanisms in BiFeO3 thin films on Pt/sapphire and Pt/Ti/SiO2/Si substrates are discussed to understand the different resistive switching behaviors.

cond-mat.mtrl-sci↗

arXiv2012

Electronic structure and magnetism in M(=IA, IIA)C compounds with the rocksalt structure

Electronic structures of MC where M is the alkali and alkaline earth metals with the rocksalt structure are calculated by full potential density functional codes. We find that the spin magnetic moment in the compounds is mainly contributed by the spin polarized p-orbitals of carbon. The large distance between the carbon makes the p-orbitals localized, which induces magnetic instability according to the Stoner criterion. The electronic structure can be mapped to the rigid band model. SrC, BaC and RaC are half-metals, while KC, RbC and CsC are magnetic semiconductors

cond-mat.mtrl-sci↗

arXiv2012

Comment on "First-principles studies on magnetic properties of rocksalt structure $M$C ($M$=Ca,Sr, and Ba) under pressure"[Appl. Phys. Lett. 98,182501(2011)]

In this comment on 'First-principles studies on magnetic properties of rocksalt structure MC(M=Ca, Sr, and Ba) under pressure'[Appl. Phys. Lett. 98, 182501 (2011)]" we found that their results of the original paper are from nonconverged calculation with respect to the k-point mesh, because they used too few k-points. This gives meaningless results presented in Fig. 1, 2 and 3 in the paper. We recalculated the correpsonding curves.

cond-mat.mtrl-sci↗

arXiv2011

Control of rectifying and resistive switching behavior in BiFeO3 thin films

BiFeO3 thin films have been grown on Pt/Ti/SiO2/Si substrates with pulsed laser deposition using Au as the top electrode. The resistive switching property of the Au/BiFeO3/Pt stack has been significantly improved by carefully tuning the oxygen pressure during the growth, and a large switching ratio of ~4500 has been achieved. The deposition pressure modifies the concentration of oxygen vacancies and the rectifying behavior of the Au/BiFeO3 junction, and consequently influences the resistive switching behavior of the whole stack. The switching takes place homogeneously over the entire electrode, and shows a long-term retention.

cond-mat.mtrl-sci↗