Mechanisms of stress generation and relaxation during pulsed laser deposition of epitaxial Fe-Pd magnetic shape memory alloy films on MgO

Mechanical stress generation during epitaxial growth of Fe–Pd thin films on MgO from pulsed laser deposition is a key parameter for the suitability in shape memory applications. By employing in situ substrate curvature measurements, we determine the stress states as a function of film thickness and composition. Depending on composition, different stress states are observed during initial film growth, which can be attributed to different misfits. Compressive stress generation by atomic peening is observed in the later stages of growth. Comparison with ex situ x-ray based strain measurements allows integral and local stress to be distinguished and yields heterogeneities of the stress state between coherent and incoherent regions. In combination with cross-sectional TEM measurements the relevant stress relaxation mechanism is identified to be stress-induced martensite formation with (111) twinning

Partial substitution of Co and Ge for Fe and B in Fe-Zr-B-Cu alloys: microstructure and soft magnetic applicability at high temperature

The partial substitutions of Co for Fe and Ge for B are studied for a Fe83-xCoxZr6B10-yGeyCu1 alloy series (x = 0, 5 and 20; y = 0 and 5) as a possible way to enhance the high temperature applicability of NANOPERM alloys. The devitrification process, the nanocrystallization kinetics and the nanocrystalline microstructure are similar for all the studied alloys. Good soft magnetic properties are observed even at a high crystalline volume fraction of bcc -Fe nanocrystals, which are stable up to ~1000 K. The partial substitution of Co for Fe is very effective to increase the Curie temperature of the residual amorphous matrix (TCAM). Although the substitution of Ge for B is ineffective to increase TCAM, a clear increase of the saturation magnetization with respect to the Ge-free alloy can be observe

The Effect of Language Type and Perceived Controllability on Stigma and Compassion

Previous research suggests that mental health stigma creates significant barriers to treatment seeking and adherence, diminishes treatment outcomes, and motivates social rejection towards people experiencing mental illness; by contrast, compassion seems to offer protective effects, improving treatment outcomes and helping behavior. The current work extends the established literature by experimentally examining the independent and interactive effects of two factors theorized to influence stigma and compassion: controllability and language. Participants read vignettes about hypothetical mental illnesses explained with a genetic attribution (indicating low controllability) or a behavioral attribution (indicating high controllability) and completed measures of perceived controllability, stigma, and compassion. We found that genetic etiology, compared to behavioral etiology, decreased stigma and increased compassion. Although not statistically significant, preliminary evidence suggests that language might interact with etiology to affect stigma. In the behavioral etiology condition, identity-first language (compared to person-first) exacerbated stigma, whereas, in the genetic etiology condition, this effect was descriptively reversed, though statistically nonsignificant. Our findings provide evidence that emphasizing the contribution of uncontrollable factors (e.g., genetics) to psychopathology could help reduce stigma and increase compassion for people experiencing mental illness. Language may also interact with controllability to inform stigma. This work could aid in advising empathetic and supportive language practices dependent on condition characteristics (e.g., perceived controllability), however, replication is needed to demonstrate the reliability of these effects

Monolithic growth of ultra-thin Ge nanowires on Si(001)

Self-assembled Ge wires with a height of only 3 unit cells and a length of up to 2 micrometers were grown on Si(001) by means of a catalyst-free method based on molecular beam epitaxy. The wires grow horizontally along either the [100] or the [010] direction. On atomically flat surfaces, they exhibit a highly uniform, triangular cross section. A simple thermodynamic model accounts for the existence of a preferential base width for longitudinal expansion, in quantitative agreement with the experimental findings. Despite the absence of intentional doping, first transistor-type devices made from single wires show low-resistive electrical contacts and single hole transport at sub-Kelvin temperatures. In view of their exceptionally small and self-defined cross section, these Ge wires hold promise for the realization of hole systems with exotic properties and provide a new development route for silicon-based nanoelectronics.Comment: 23 pages, 5 figure

Ductile ultrafine-grained Ti-based alloys with high yield strength

The authors report on ductile ultrafine-grained (Ti0.72Fe0.28)100−xTax (0 ⩽ x ⩽ 4) alloys with not only high fracture strength but simultaneously high yield strength exceeding 2000 MPa along with distinct plasticity, which are superior to high-strength Ti-based bulk metallic glasses and bimodal composites. All alloys mainly consist of β-Ti and FeTi solid solutions but display different microstructures. The alloys exhibit a high fracture strength \u3e2500 MPa and a high yield strength \u3e2000 MPa as well as large plasticity of ∼ 5%–7.5%. The microstructure-property correlation of these ultrafine-grained alloys is discussed

Deformation-induced nanoscale high-temperature phase separation in Co-Fe alloys at room temperature

Instead of applying severe plastic deformation, high-temperature heat treatment or high pressure, grain refinement and high-temperature phase separation induced by deformation in single-phase body-centered-cubic (bcc) coarse-grained Co–Fe alloys have been achieved by simple room-temperature compression. The alloys exhibit large plasticity over 140% without fracture. Phase separation from the bcc phase to nanoscale face-centered-cubic Fe and Co phases, which generally occurs at high temperature above ∼ 1150 K, is formed in the deformed samples. The possible mechanisms are shear deformation and deformation-enhanced atomic diffusion rather than the temperature rise during deformatio

Carbon nanotube synthesis via ceramic catalysts

The potential for ceramics as catalysts for carbon nanotubes (CNTs) formation exceed that of metal catalysts in that ceramics can serve not only as a catalyst particle for CNT nucleation/growth as found with metal catalyst, but they can also serve as a template for the synthesis of carbon nanostructures. They can only be purified more readily. Here we present studies on the growth of CNTs from ceramics in laser pyrolyses and chemical vapor deposition (CVD) routes. We show CNT growth from both nanowires and ceramic particles. In addition, doping of the CNTs an also be achieved through the use of ceramic catalysts. Since ceramic materials are easily removed from the as-produced samples as compared to metal catalysts, they are attractive for further application, e.g., in carbon-based electronics