Ning-Bin Zhang

University of Limerick | UL · Department of Physics

Retention failure is deleterious on ferroelectric domain stability, resulting in data loss in ferroelectric memories. However, the understanding of the origin of retention failure remains a challenge for the lack of a direct experimental evidence. Here, using a combination of piezoelectric force microscopy, atomic-scale scanning transmission electr...

The physical properties of perovskite oxides are very sensitive to oxygen vacancy structures, and an unambiguous acquaintance of vacancy structures of thin films is the precondition for applications of many functional devices. Here, we report critical thickness control over oxygen vacancy ordering structure in epitaxial LaCoO3-x (LCO) thin films ch...

Phase coexistence in ferroelectric oxide films displays complex phase competitions and transformation which suggest new multiple-coupled properties. Here we have successfully engineered the coexistence of flux-closure and a1/a2 phases in tensile-strained PbTiO3 films sandwiched between GdScO3 substrate and a SrTiO3 layer. Moreover, by using in-situ...

Ferroelectrics exhibit polarization tunable resistance switching behaviors, which are promising for next-generation non-volatile memory devices. For technological applications, thinner nanoscale arrays are expected, which feature with higher density and larger ON/OFF (RON/OFF) ratios in the metal/ferroelectrics/semiconductor heterojunction. Here, w...

Controlling domain width, orientation, and patterns in oxide ferroelectrics are not only important for fundamental research but also for potential electronic application. Here, a series of PbTiO 3 thin films under various cooling rates were deposited on (110)-oriented NdScO 3 substrates by pulsed laser deposition and investigated by using conventio...

Domain behavior of (111)- oriented perovskite ferroelectric films is significantly different from (001)-/(101)- oriented ones, resulting in enhancing property responses such as a superior susceptibility and a reduced coercive field. However, the domain structures and evolutions with the thickness of (111)-oriented ferroelectric films, which are cru...

Topological defects showing exotic properties and diverse functionalities provide us a potential utilization in nanoscale electronic devices. However, the formation mechanism and density manipulation of topological defects such as center-type domains which are crucial for applications remain elusive. Usually, these center-type domains are generated...

Oxygen vacancy configurations and concentration are coupled with the magnetic, electronic and transport properties of perovskite oxides, manipulating the physical properties by tuning vacancy structures of thin films is crucial for applications of many functional devices. In this study, we report a direct atomic resolution observation of preferred...

Coexistence of two phases creates a morphotropic phase boundary in perovskite oxides, which can provide large piezoelectric response, generating it a well suited system for probe-based memories and actuator applications. The coexistence of two phases in thin films is proposed to be induced by epitaxial constraints from substrates or chemical compos...