84 research outputs found
Interface-dominated Growth of a Metastable Novel Alloy Phase
A new \textit{D0} metastable phase of CuAu is found to grow at the
interfaces of Au/Cu multilayers deposited by magnetron sputtering. The extent
of formation of this novel alloy phase depends upon an optimal range of
interfacial width primarily governed by the deposition wattage of the
dc-magnetron used. Such interfacially confined growth is utilized to grow a
300 nm thick Au/Cu multilayer with thickness of each layer nearly equal
to the optimal interfacial width which was obtained from secondary ion mass
spectrometry (SIMS) data. This growth technique is observed to enhance the
formation of the novel alloy phase to a considerable extent. SIMS depth profile
also indicates that the mass fragment corresponding to CuAu occupies the
whole film while x-ray diffraction (XRD) shows almost all the strong peaks
belonging to the \textit{D0} structure. High resolution cross-sectional
transmission electron microscopy (HR-XTEM) shows the near perfect growth of the
individual layers and also the lattice image of the alloy phase in the
interfacial region. Vacuum annealing of the alloy film and XRD studies indicate
stabilization of the \textit{D0} phase at 150C. The
role of interfacial confinement, the interplay between interfacial strain and
free energy and the hyperthermal species generated during the sputtering
process are discussed.Comment: Accepted in Journal of Materials Researc
Tailoring the interfacial magnetic interaction in epitaxial LaSrMnO/SmCaMnO heterostructures
Interface engineering in complex oxide heterostructures has developed into a
flourishing field as various intriguing physical phenomena can be demonstrated
which are otherwise absent in their constituent bulk compounds. Here we present
LaSrMnO (LSMO) / SmCaMnO (SCMO) based
heterostructures showcasing the dominance of antiferromagnetic interaction with
increasing interfaces. In particular, we demonstrate that exchange bias can be
tuned by increasing the number of interfaces; while, on the other hand,
electronic phase separation can be mimicked by creating epitaxial multilayers
of such robust charge ordered antiferromagnetic (CO-AF) and ferromagnetic (FM)
manganites with increased AF nature, which otherwise would require
intrinsically disordered mixed phase materials. The origin of these phenomena
is discussed in terms of magnetic interactions between the interfacial layers
of the LSMO/SCMO. A theoretical model has been utilized to account for the
experimentally observed magnetization curves in order to draw out the complex
interplay between FM and AF spins at interfaces with the onset of charge
ordering.Comment: 8 figure
- β¦