Function Of In-plane Angle Research Articles

Ultrasonic characterization on sequences of CFRP composites based on modeling and motorized system

Composites are a material class for which nondestructive material property characterization is as important as flaw detection. Laminates of fiber reinforced composites often possess strong in-plane elastic anisotropy attributable to the specific fiber orientation and layup sequence when waves are propagating in the thickness direction of composite laminates. So the layup orientation greatly influences its properties in a composite laminate. It could result in the part being rejected and discarded if the layup orientation of a ply is misaligned. A nondestructive technique would be very beneficial, which could be used to test the part after curing and requires less time than the optical test. Therefore a ply-by-ply vector decomposition model has been developed, simplified, and implemented for composite laminates fabricated from unidirectional plies. This model decomposes the transmission of a linearly polarized ultrasound wave into orthogonal components through each ply of a laminate. Also in order to develop these methods into practical inspection tools, motorized system have been developed for different measurement modalities for acquiring ultrasonic signals as a function of in-plane angle. It is found that high probability shows between the model and tests developed in characterizing cured layups of the laminates.

Large in-plane anisotropies in Co/Re superlattices: What’s happening at the interface?

We have performed magnetization and 36 GHz ferromagnetic resonance measurements as a function of in-plane angle and Co layer thickness in order to determine the interface anisotropies in epitaxial hcp (101̄0) Co(x)/Re(1.2 nm) superlattices (1.0 nm<x<3.5 nm), whose Co c axis lies in the film plane. The linear dependence of magnetization upon inverse Co layer thickness indicates the bulk of the Co layer has a magnetization of 1390 emu/cm3, and nonmagnetic Co within 0.5 nm of each Re interface. The angular variation in the resonance position yields out-of-plane, and first and second order uniaxial in-plane anisotropies. These coefficients are plotted as a function of the inverse magnetic Co layer thickness (1/tCo), yeilding their interface and volume contributions. The volume out-of-plane term is 10.7×106 erg/cm3, which compares favorably with the 12.3×106 erg/cm3 expected from shape anisotropy. Despite the c axis being in plane, a significant out-of-plane interface energy of −0.074 erg/cm2 was detected, which favors out-of-plane magnetization. The first order uniaxial in-plane term is independent of tCo. Its average value of 1.2×106 erg/cm3 is a factor of 4 smaller than that observed in macroscopic Co. The second order in-plane uniaxial term does vary linearly with 1/tCo, yielding volume and interface contributions of 1.3×105 erg/cm3 (a factor of 10 smaller than that observed in macroscopic Co and −7×10−4 erg/cm2, respectively).

The Effects of Strain on The Magnetic Anisotropy of Doped Manganite Thin Films

ABSTRACTWe show the importance of the role of strain in doped manganite perovskite materials by revealing the dominance of stress anisotropy effects over magnetocrystalline anisotropy effects in the magnetic anisotropy of these films. In order to measure magnetic anisotropy in the plane of the films, remnant magnetization was measured as a function of in-plane angle. The (110) La0.7Sr0.3MnO3 films reveal a twofold symmetry while the (100) films have fourfold symmetry. Temperature dependence of the magnetic anisotropy of La0.7Sr0.3MnO3 films reveals decreasing anisotropy as the Curie temperature is approached.