Biaxial Components Research Articles

Shaping the Design Features of a Dynamometer for Measuring Resistance Biaxial Components of Symmetrical Coulters.

The article lays out the methodology for shaping the design features of a strain gauge transducer, which would make it possible to study forces and torques generated during the operation of symmetrical seeder coulters. The transducers that have been known up until now cannot be used to determine forces and torques for the coulter configuration adopted by the authors. For this purpose, the design of the transducer in the form of strain gauge beams was used to ensure the accumulated stress concentration. A detailed design was presented in the form of a 3D model, along with a transducer body manufactured on its basis, including the method for arranging the strain gauges thereon. Moreover, the article discusses the methodology of processing voltage signals obtained from component loads. Particular attention was paid to the methodology of determining the load capacity of the transducer structure, based on finite element method (FEM). This made it possible to choose a transducer geometry providing the expected measurement sensitivity and, at the same time, maintaining the best linearity of indications, insignificant coupling error, and a broad measurement range. The article also presents the characteristics of the transducer calibration process and a description of a special test stand designed for this purpose. The transducer developed within the scope of this work provides very high precision of load spectrum reads, thus enabling the performance of a detailed fatigue analysis of the tested designs. Additionally, the versatility it offers makes it easy to adapt to many existing test stands, which is a significant advantage because it eliminates the need to build new test stands.

Dynamic magnetic properties of amorphous Fe80B20 thin films and their relation to interfaces

We present a ferromagnetic resonance study of the dynamic properties of a set of amorphous Fe-B films deposited on Corning Glass® and MgO (001) substrates, either with or without capping. We show that the in plane anisotropy of the MgO grown films contains both uniaxial and biaxial components whereas it is just uniaxial for those grown on glass. The angular dependence of the linewidth strongly differs in terms of symmetry and magnitude depending on the substrate and capping. We discuss the role of the interfaces on the magnetization damping and the generation of the anisotropy. We obtained values of the intrinsic damping parameters comparable to the lowest ones reported for amorphous films of similar compositions.

Thickness‐Dependent Strain Evolution of Epitaxial SrTiO3 Thin Films Grown by Ion Beam Sputter Deposition

AbstractEpitaxial SrTiO3 (STO) thin films are grown on vicinal (001)‐oriented LaAlO3 (LAO) substrates with various thicknesses (3–108 nm) by an ion beam sputter deposition (IBSD). Thickness‐dependent strain in the STO films is investigated comprehensively through the X‐ray analysis. The STO films grow on the LAO substrates under a compressive strain along in‐plane direction (a‐ and b‐axes) and a tensile strain along the growth direction (c‐axis). With increasing film thickness, the STO unit cells evolve from more to less tetragonal structure, indicating the occurrence of strain relaxation. Quantitative strain analysis is also carried out for all STO films in terms of biaxial and hydrostatic components. It is found that the major cause of strain in STO films is caused by biaxial component over hydrostatic component. The surface morphology of STO films exhibit a step‐and‐terrace structure with roughness close to the LAO substrate (approx. 0.1 nm), indicating a 2D growth mode. However, as the film thickness increases, the surface terrace become rougher, which is caused by the effect of strain relaxation.

Controlled growth of GaN nanowires by pulsed metalorganic chemical vapor deposition

Controlled and reproducible growth of GaN nanowires is demonstrated by pulsed low-pressure metalorganic chemical vapor deposition. Using self-assembled Ni nanodots as nucleation sites on (0001) sapphire substrates we obtain nanowires of wurtzite-phase GaN with hexagonal cross sections, diameters of about 100nm, and well-controlled length. The nanowires are highly oriented and perpendicular to the growth surface. The wires have excellent structural and optical properties, as determined by x-ray diffraction, cathodoluminescence, and Raman scattering. The x-ray measurements show that the nanowires are under a complex strain state consistent with a superposition of hydrostatic and biaxial components.

Control and elimination of biaxial strain in laser-ablated epitaxial BaxSr1−xTiO3 films

We report the in-plane (a) and out-of-plane (c) lattice parameters of epitaxial laser-ablated Ba0.4Sr0.6TiO3 films on MgO for a range of O2 deposition pressures (40–250 mTorr) near the observed transition from a<c to a>c. From these lattice parameters, we calculate the residual strain and stress in terms of hydrostatic and biaxial components. Both components increase sharply with O2 pressure between 85 and 100 mTorr, consistent with ion peening effects. Postdeposition annealing decreases the hydrostatic strain, but increases the biaxial tension. For both as-deposited and annealed films, we obtain samples with no biaxial strain (i.e., a=c), within experimental uncertainty. Overall, the strain is a combination of hydrostatic and biaxial components, both of which affect the dielectric response. Therefore, consideration and control of both types of strain is important for the optimum performance of devices such as tunable microwave devices and high-density memories.

Hydrostatic and Biaxial Strain in BaxSr1-xTiO3Films Grown by Pulsed Laser Deposition

AbstractWe grew BaxSr1−xTiO3(BST) films on MgO single crystal substrates by pulsed laser deposition (PLD). We report the in-plane (a) and out-of-plane (c) lattice parameters of BST films deposited in a range of O2deposition pressures [P(02)], as measured by asymmetric rocking curve diffraction. As P(O2) increases, the films' biaxial strain changes from compression (a<c), to cubic (a=c), and then to tension (a>c). Furthermore, bothaandcare larger than the lattice constant for bulk BST of the same composition. This indicates the presence of a hydrostatic strain component in addition to the biaxial component. From the measured lattice parameters, we calculate the total residual strain in terms of biaxial and hydrostatic components. We also examine the effects of a post-deposition anneal. Characterizing residual strain and understanding its origin(s) are important since strain affects the dielectric properties of BST films and thereby the properties of devices which incorporate them.

Point Defects and Induced Magnetic Anisotropy in Fast Neutron Irradiated Iron

Magnetic torque measurements have been made at 77 K for a single crystal disc of pure iron before and after a fast neutron irradiation at 5 K and after successive isochronal annealings at various temperatures between 77 K and 293 K. The observed torque curve after the irradiation contains both uniaxial and biaxial components. By analyzing the irradiation-induced torque and its change during isochronal annealings, the existence of 110-dumbbells has been confirmed, and the mechanism of the aggregation of interstitials and the change in their arrangements predicted theoretically by Bullough and Perrin have experimentally been proved.