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Bismuth ferrite layers, ∼200-nm-thick, are deposited on SrRuO3-coated DyScO3(110)o substrates in a step-flow growth regime via adsorption-controlled molecular-beam epitaxy. Structural characterization shows the films to be phase pure with substrate-limited mosaicity (0.012° x-ray diffraction ω-rocking curve widths). The film surfaces are atomically smooth (0.2 nm root-mean-square height fluctuations) and consist of 260-nm-wide [11¯1]o-oriented terraces and unit-cell-tall (0.4 nm) step edges. The combination of electrostatic and symmetry boundary conditions promotes two monoclinically distorted BiFeO3 ferroelectric variants, which self-assemble into a pattern with unprecedentedly coherent periodicity, consisting of 145 ± 2-nm-wide stripe domains separated by [001]o-oriented 71° domain walls. The walls exhibit electrical rectification and enhanced conductivity. 

We systematically investigate the role of defects, introduced by varying synthesis conditions and by carrying out ion irradiation treatments, on the structural and ferroelectric properties of commensurately strained bismuth ferrite BixFe2−xO3 layers grown on SrRuO3-coated DyScO3(110)o substrates using adsorption-controlled ozone molecular-beam epitaxy. Our findings highlight ion irradiation as an effective approach for reducing through-layer electrical leakage, a necessary condition for the development of reliable ferroelectrics-based electronics. 

Abstract The ability to make controlled patterns of magnetic structures within a nonmagnetic background is essential for several types of existing and proposed technologies. Such patterns provide the foundation of magnetic memory and logic devices, allow the creation of artificial spin‐ice lattices, and enable the study of magnon propagation. Here, a novel approach for magnetic patterning that allows repeated creation and erasure of arbitrary shapes of thin‐film ferromagnetic structures is reported. This strategy is enabled by epitaxial Fe_0.52Rh_0.48thin films designed so that both ferromagnetic and antiferromagnetic phases are bistable at room temperature. Starting with the film in a uniform antiferromagnetic state, the ability to write arbitrary patterns of the ferromagnetic phase is demonstrated by local heating with a focused laser. If desired, the results can then be erased by cooling below room temperature and the material repeatedly re‐patterned. 

Abstract The role of interfacial nonidealities and disorder on thermal transport across interfaces is traditionally assumed to add resistance to heat transfer, decreasing the thermal boundary conductance (TBC). However, recent computational studies have suggested that interfacial defects can enhance this thermal boundary conductance through the emergence of unique vibrational modes intrinsic to the material interface and defect atoms, a finding that contradicts traditional theory and conventional understanding. By manipulating the local heat flux of atomic vibrations that comprise these interfacial modes, in principle, the TBC can be increased. In this work, experimental evidence is provided that interfacial defects can enhance the TBC across interfaces through the emergence of unique high‐frequency vibrational modes that arise from atomic mass defects at the interface with relatively small masses. Ultrahigh TBC is demonstrated at amorphous SiOC:H/SiC:H interfaces, approaching 1 GW m⁻²K⁻¹and are further increased through the introduction of nitrogen defects. The fact that disordered interfaces can exhibit such high conductances, which can be further increased with additional defects, offers a unique direction to manipulate heat transfer across materials with high densities of interfaces by controlling and enhancing interfacial thermal transport.