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A circular membrane clamped at the periphery is allowed to adhere to or to delaminate from a planar surface of a cylindrical punch in the presence of intersurface forces with finite range and magnitude. Assuming a uniform disjoining pressure within the cohesive zone at the delamination front, the adhesion-delamination mechanics is obtained by a thermodynamic energy balance. Interrelations between the instantaneous applied load, punch displacement, and contact circle, and the resulting critical thresholds of 'pinch-off,' 'pull-off' and 'pull-in' are derived from the first principles. Two limiting cases are obtained: (i) intersurface force with long range and small magnitude in reminiscence of the classical Derjaguin--Muller--Toporov (DMT) model and (ii) short range and large magnitude alluding to the Johnson-Kendall-Roberts (JKR) model. The DMT-JKR transitional behavior has significant impacts on adhesion measurements, microelectromechanical systems, and life-sciences. [DOI: 10.1115/1.3112745] Keywords: thin film adhesion, delamination, surface force, disjoining pressure, cohesive zone

We measured the second harmonic generation response of a thin film consisting of chiral molecules with four wave plates having different retardation coefficients. By means of the fitting procedure described in a previously reported formalism, we demonstrated that a single set of tensor components of second order surface nonlinearities fits all the data. Our results provide clear experimental evidence for the validity of this method, which can find applications in the studies of chiral structures and achiral anisotropic materials. OCIS codes: 160.1585, 190.4160.

The adsorption of ruthenium-dye molecules out of ethanol solution onto TiO2 particles of nanoporous TiO2 films was used to study the molecules' diffusion through these layers by means of optical absorption spectrometry. These diffusion constants for diffusion through the nanoporous network are up to 3 orders of magnitude lower than in bulk ethanol and are discussed with respect to the properties of the nanoporous material.

Monte Carlo simulations of disjoining-pressure isotherms for soluble-surfactant-stabilized free thin films are presented. A disjoining-pressure isotherm is defined such that films of all thicknesses on that isotherm are in equilibrium with the same infinite reservoir of surfactant and solvent.

A new series of mixed phylene-thiophene oligomers with terminal n-hexyl groups is synthesized and characterized both as bulk solids and thin films. The compounds are thermally stable, and the thin films adopt microstructures with lattice spacings suggestive of molecular alignment along the substrate normal.

Using an imaging mode based on the adjustment of a negative value of the spherical-aberration coefficient of the objective lens of a transmission electron microscope, we successfully imaged all types of atomic columns in the dielectric SrTi[O.sub.3] and the superconductor Y[Ba.sub.2][Cu.sub.3][O.sub.7]. In particular, we were able to view the oxygen atoms which, due to their low scattering power, were not previous[y accessible, and this allowed us to detect local nonstoichiometries or the degree of oxygen-vacancy ordering. This technique offers interesting opportunities for research into oxides, minerals, and ceramics. In particular, this holds for the huge group of perovskite-derived electroceramic materials in which the local oxygen content sensitively controls the electronic properties., Thin films of Ba- and Sr-based perovskites have great potential for application, in particular as high-permittivity dielectrics in microelectronics or nonvolatile memory devices. Research on the structure and properties of [...]

The pulsed-laser deposition (PLD) technique is currently used in research laboratories to obtain thin films from a broad range of materials even with a complex composition. The differences in the crystalline properties of ZnO films grown by laser ablation, using either nanosecond or femtosecond pulsed-laser deposition (PLD) is presented.

Research is presented illustrating the development of experimental techniques and algorithms for extracting the complex dielectric function of thin films of quantum dots.

The effects of the substrates on structural and magnetic properties of Co:TiO2 films are examined. It is observed that the films on Si substrates are rutile and the films on LAO and STO substrates are single phased anatase.

The spontaneous covalent growth of monomolecular adlayers on boran-doped diamond (BDD) thin films is described. The data obtained disclosed a large orientational distribution of chromophores on the BDD surface, consistent with the mesoscopic morphology of the system.

The magnetic and magnetotransport properties of ultrathin, discontinuous [La.sub.0.7][Ca.sub.0.3]Mn[O.sub.3] films were studied. The zero field resistivity indicates the granular nature of the film in agreement with atomic force microscopy imaging and the strongly reduced magnetization. The magnetoresistance is very large exceeding the theoretical limit for spin-polarized tunneling in granular ferromagnets. A modification of this model is presented that might explain these large magnetoresistance values. Index Terms--[La.sub.0.7][Ca.sub.0.3]Mn[O.sub.3], magnetic films, magnetoresistance, tunneling.

We have characterized [Zn.sub.1-x][Co.sub.x]O thin films grown on sapphire (0001) substrates by pulsed laser deposition. We have found for x = 0.25 that inhomogeneous [Zn.sub.1-x][Co.sub.x]O films with wurtzite ZnO phase mixed with rock-salt CoO and hexagonal Co phases are formed when the growth temperature ([T.sub.g]) is relatively high ([??] 600[degrees]C) and the [O.sub.2] pressure ([P.sub.O.sub.2]) is fairly low ([??][10.sup.-5] torr). The presence of the Co clusters leads to room temperature ferromagnetism. Homogeneous [Zn.sub.1-x][Co.sub.x]O alloy films with wurtzite structure are predominantly paramagnetic. High-quality epitaxial [Zn.sub.1-x][Co.sub.x]O alloy films are formed at a growth condition of [T.sub.g] = 600[degrees]C and [P.sub.O.sub.2] = [10.sup.-5] torr. Under this optimized growth condition, Co can be dissolved into ZnO up to around 40%. Photoinminescence spectra and electrical properties of [Zn.sub.1-x][Co.sub.x]O strongly depend on the Co content. Index Terms--Diluted magnetic semiconductors, pulsed laser deposition, spin electronics, ZnCoO.

The magnetic properties of NiFe and FeCoN thin films were examined using Kerr microscopy after [Ga.sup.+] focused-ion-beam (FIB) irradiation. Magneto-optic characterizations of 30 [micro]m x 30 [micro]m irradiated surface areas showed that the magnetization was reduced in approximately linear proportion to the [Ga.sup.+] ion dose. Above an ion dose of approximately 0.6 nC/[micro][m.sup.2] (3.8 X [10.sup.17] ions/[cm.sup.2]), little sign of the Kerr rotation could be found. The effect of the irradiation on the coercive force was also examined. Little effect of the beam on the coercivity of NiFe was seen, but an increase of coercivity was seen in FeCoN. The reduction of the Kerr rotation is attributed to magnetic moment loss caused by Ga implantation into the magnetic thin films. This loss has been quantified and is relevant to pole trimming for high-density magnetic recording heads. Index Terms--FeCoN, FIB irradiation, Ga implantation, Kerr microscopy, magnetic properties, NiFe.

The soft magnetic properties of FeCo films, sandwiched by thin NiFe or NiFeCr films, are discussed in relation to the microstructure. Ta/NiFe(Cr)(5 nm)/FeCo(100 nm)/ NiFe(Cr)(5 nm)/Ta films prepared using the UHV sputtering process with pure Ar plasma show bcc-(110) preferred grain orientation of FeCo layer with the direction sharply perpendicular to the film plane, resulting in soft magnetic properties. No significant difference in soft magnetic properties was observed by the use of nonmagnetic NiFeCr layers instead the NiFe layers, moreover, by varying FeCo composition between 25 and 30 at % Co. The best thickness of the FeCo layer in order to realize soft magnetic properties was found to be ~100 nm in the present study, with a high saturation magnetization of 2.3 T. An addition of [N.sub.2] gas to Ar plasma during film deposition did not lead to an improvement of the soft magnetic properties. A film of [[FeCo(100 m)/NiFe(5 nm)].sub.4] layer structure was subjected to the fabrication of single-pole-type recording head, and it is successfully demonstrated that the film has a sufficient softness to be used for the recording head application. Index Terms--FeCo films, lattice strain, preferred grain orientation, saturation magnetization, soft magnetic properties.

The experimental observation on a threshold thickness of crystallization below which the crystallinity of the films drops precipitously in spin cast films of poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] copolymer is presented. This threshold thickness is directly linked to the crystal lamellar size along the film thickness direction.

The intrinsic perpendicular magnetic anisotropy constant [K.sub.u], for [(Fe-Co-Ni).sub.50][Pt.sub.50] quaternary alloy and [(Fe-Cr).sub.50][Pt.sub.50] alloy thin films is discussed as a function of structure and composition. Both [M.sub.s] and the estimated [K.sub.u], values obtained by the extrapolation to order parameter S = 1 using the dependence of [K.sub.u] on S become maximum at the valence electron number [n.sub.elect] = 8, being independent of alloy system. The magnetic anisotropy is determined to the first approximation by the Fermi energy, Which changes with the number of electrons, but not by the band structure itself. Index Terms--[(Fe-Co-Ni-Cr).sub.50][Pt.sub.50] ordered alloys, magnetic anisotropy, order parameter, valence electron number.