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Magnons and phonons are fundamental quasiparticles in a solid and can be coupled together to form a hybrid quasi-particle. However, detailed experimental studies on the underlying Hamiltonian of this particle are rare for actual materials. Moreover, the anharmonicity of such magnetoelastic excitations remains largely unexplored, although it is essential for a proper understanding of their diverse thermodynamic behaviour and intrinsic zero-temperature decay. Here we show that in non-collinear antiferromagnets, a strong magnon–phonon coupling can significantly enhance the anharmonicity, resulting in the creation of magnetoelastic excitations and their spontaneous decay. By measuring the spin waves over the full Brillouin zone and carrying out anharmonic spin wave calculations using a Hamiltonian with an explicit magnon–phonon coupling, we have identified a hybrid magnetoelastic mode in (Y,Lu)MnO3 and quantified its decay rate and the exchange-striction coupling term required to produce it., The properties of magnetic, crystalline solids can be described in terms of quantum particles of spin-wave and lattice-vibration energy, known as magnons and phonons respectively. Here, the authors show that strong magnon-phonon coupling in a noncollinear antiferromagnet can create magnetoelastic excitations.

Understanding the magnetic excitations in high-temperature (high-T(c)) copper-oxide superconductors is important because they may mediate the electron pairing for superconductivity(1,2). By determining the wavevector (Q) and energy ((h) over bar omega) dependence of the magnetic excitations, it is possible to calculate the change in the exchange energy available to the superconducting condensation energy(3-5). For the high-T(c) superconductor YBa(2)Cu(3)O(6+x), the most prominent feature in the magnetic excitations is the resonance(6-12). Suggestions that the resonance contributes a major part of the superconducting condensation(4,13) have not gained acceptance because the resonance is only a small portion of the total magnetic scattering(12-14). Here, we report an extensive mapping of magnetic excitations for YBa(2)Cu(3)O(6.95) (T(c) similar to 93 K). Absolute intensity measurements of the full spectra allow us to estimate the change in the magnetic exchange energy between the normal and superconducting states, which is about 15 times larger than the superconducting condensation energy(15,16) - more than enough to provide the driving force for high-T(c) superconductivity in YBa(2)Cu(3)O(6.95).

We have recently used inelastic neutron scattering to measure the magnetic excitation spectrum of La 1.875 Ba 0.125 CuO 4 up to 200 meV. This particular cuprate is of interest because it exhibits static charge and spin stripe order. The observed spectrum is remarkably similar to that found in superconducting YBa 2 Cu 3 O 6+ x and La 2− x Sr x CuO 4 ; the main differences are associated with the spin gap. We suggest that essentially all observed features of the magnetic scattering from cuprate superconductors can be described by a universal magnetic excitation spectrum multiplied by a spin gap function with a material-dependent spin-gap energy.

Full three-dimensional diffuse neutron scattering data have been recorded from a single crystal of Pb(Zn1/3Nb2/3)O3(PZN) at 300 K using the time-of-flight Laue technique on the SXD single-crystal instrument at ISIS. The data show a series of diffuse rods of scattering oriented parallel to each of the six 〈1 1 0〉 crystal directions. Monte Carlo simulation has been used to demonstrate that the diffuse rods are caused by planar nanodomains oriented normal to the 〈1 1 0〉 directions. Within these domains, there are correlated displacements of the atoms away from their average site positions. In order to explain the systematic absence of some rods of scattering in the (h k 1) data but the presence of all rods in the (h k 0) data, it is necessary that the displacement of an O atom is of opposite sign to that of its neighbouring Pb atoms. This is explained in terms of a model based on the fact that Pb2+possesses a lone pair of electrons, giving the Pb ion directionality.

Experimental realizations of model magnetic systems--ones in which the interactions between the magnetic ions have a particularly simple form--are test-beds for our fundamental understanding of magnetic phenomena. If we are to understand the unusual properties of complex and potentially useful materials in which magnetism plays an important role, such as colossal magnetoresistive oxides or high temperature superconductors, we must also understand the properties of simple systems. SrCuO{sub 2} is an example of a one-dimensional magnetic system in which the characteristic energy of excitations from the magnetic ground state is comparable to that of charge motion along the chains. Our results show that the spectrum of magnetic excitations is nevertheless well described by that for the limiting case when charge and spin dynamics are separable.

Detailed magnetic and transport properties of electron-doped Bi0.125Ca0.875 MnO3 materials are reported. Low field magnetization measurements provide evidence for ferromagnetic Curie–Weiss behaviour at higher temperatures and an antiferromagnetic state below TN = 109 K, which supports a ferromagnetic component. High field () DC magnetization measurements (5–300 K) show a strongly nonlinear field response below and far above the ordering temperature. The residual magnetic moment and coercive field, in the ordered state, are, however, exceptionally small. These results are discussed in terms of the FM coupling of spins into clusters. The possible coupling of these clusters to the AF staggered magnetization (below TN) and to AF fluctuations (above TN) is discussed. The magnetic effects appear to be consistent with canted antiferromagnetism, however, FM segregation is not ruled out. The high field magnetoresistance (up to 30 T) appears to be governed by a field-induced reduction in the doped carrier localization. The glassy character of the cluster magnetic response was investigated by measuring the frequency dependent AC susceptibility and time/history evolution of the low field magnetization. Glassy behaviour in the cluster response is indeed observed and is discussed. The differentiation of cluster glass versus canted-AF origins of the time/history effects is still an open issue.

The breakdown of magnons, the quasiparticles of magnetic systems, has rarely been seen. By using an inelastic neutron scattering technique, we report the observation of spontaneous magnon decay in multiferroic ${\mathrm{LuMnO}}_{3}$, a simple two dimensional Heisenberg triangular lattice antiferromagnet, with large spin $S=2$. The origin of this rare phenomenon lies in the nonvanishing cubic interaction between magnons in the spin Hamiltonian arising from the noncollinear 120\ifmmode^\circ\else\textdegree\fi{} spin structure. We observed all three key features of the nonlinear effects as theoretically predicted: a rotonlike minimum, a flat mode, and a linewidth broadening, in our inelastic neutron scattering measurements of single crystal ${\mathrm{LuMnO}}_{3}$. Our results show that quasiparticles in a system hitherto thought of as ``classical'' can indeed break down.

Lithography becomes much more challenging when CD shrinks to 22nm nodes. Since EUV is not ready, double patterning combined with Resolution Enhancement Technology (RET) such as shrink techniques seems to be the most possible solution. Companies such as TSMC [1] and IBM [2] etc. are pushing out EUV to extend immersion ArF lithography to 32nm/22nm nodes. Last year, we presented our development work on 32nm node contact (50nm hole at 100nm pitch) using dry ArF lithography by double patterning with SAFIER shrink process [3] . To continue the work, we further extend our dry litho capability towards the 22nm node. We demonstrated double patterning capability of 40nm holes at 80nm pitch using ASML XT1400E scanner. It seems difficult to print pitches below 140nm on dry scanner in single exposure which is transferred into 70nm pitch with double patterning. To push the resolution to 22nm node and beyond, we developed ArF immersion process on ASML XT1700i-P system at the College of Nanoscale Science and Engineering (Albany, NY) combined with a SAFIER process. We achieved single exposure process capability of 25nm holes at 128nm pitch after shrink. It enables us to print ~25nm holes at pitch of 64nm with double patterning. Two types of hard mask (HM), i.e. TIN and a-Si were used in both dry and immersion ArF DP processes. The double patterning process consists of two HM litho-shrink-etch steps. The dense feature is designed into two complementary parts on two masks such that the density is reduced by half and minimum pitch is increased by at least a factor of 2 1/2 depending on design. The complete pattern is formed after the two HM litho-shrink-etch steps are finished.

Double patterning technique is listed as the top option for 32nm technology nodes at recently updated 2007 International Technology Roadmap Semiconductor (ITRS). Double patterning (DP) effectively reduces the k1 factor to less than 0.25, however, various process challenges, including critical dimension uniformity (CDU), line edge and line width roughnesses (LER/LWR), and overlay, have to come up with so lutions for the industry in device manufacturing. In this study, we developed a metal hard mask and a universal dual hard mask double patterning process and demonstrated 45nm half-pitch in dark field patterning and 32nm half pitch in bright field applications by using a 0.93NA 193nm dry scanner system. By using the optimized hard mask films and Applied Materials’ Advanced Patterning Film (APF TM ) as a bottom hard mask, the universal dual hard mask double patterning scheme shows significant improvement in line edge roughness and line width roughness, achieved best results of 2nm LER and 2.5nm LWR at APF hard mask. Keywords: Double patterning (DP), hard mask (HM), 193nm dr y lithography, line edge roughness (LER), line width roughness (LWR), advanced patterning film (APF).

We use high-resolution inelastic neutron scattering to study the low-temperature magnetic excitations of the electron-doping superconductor Pr(0.88)LaCe(0.12)CuO(4-delta) (T(c) = 21 +/- 1 K) over a wide energy range (4 meVor = homegaor = 330 meV). The effect of electron doping is to cause a wave vector (Q) broadening in the low-energy (homegaor = 80 meV) commensurate spin fluctuations at (0.5, 0.5) and to suppress the intensity of spin-wave-like excitations at high energies (homegaor = 100 meV). This leads to a substantial redistribution in the spectrum of the local dynamical spin susceptibility chi''(omega), and reveals a new energy scale similar to that of the lightly hole-doped YB2Cu3O(6.353) (T(c) = 18 K).

Using the MAPS spectrometer at the ISIS spallation source, we have measured the magnetic excitations of single-crystal samples of stripe-ordered ${\mathrm{La}}_{2\ensuremath{-}x}{\mathrm{Sr}}_{x}\mathrm{Ni}{\mathrm{O}}_{4}$ with $x=0.333$ and 0.275. The full two-dimensional spin-wave dispersions were obtained using incident energies of 60 and 160 meV. To analyze the excitations, we have evaluated a spin-only Hamiltonian describing diagonal, site-centered stripes in the linear spin-wave approximation. Besides the superexchange energy $J$ within antiferromagnetic domains, we have considered effective exchange couplings ${J}_{1}$ and ${J}_{2}$ across a charge stripe coupling second-neighbor Ni sites along Ni-O bond directions and along the plaquette diagonal, respectively. From least-squares fits of the model to the measurements on the $x=1∕3$ sample at $T=10\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, we find that the dispersions are well described by a model using just $J$ and ${J}_{1}$, but not $J$ and ${J}_{2}$. Consistent with an analysis of previous measurements, we find that $J$ is about 90% of the superexchange energy of undoped ${\mathrm{La}}_{2}\mathrm{Ni}{\mathrm{O}}_{4}$ and ${J}_{1}∕J\ensuremath{\approx}0.5$. The excitations observed for $x=0.275$ are surprisingly similar to those for $x=1∕3$, despite the differing magnetic-ordering wave vectors; the main difference is a broadening of the excitations for $x=0.275$. For both samples, we find that one spin-wave branch has a gap of $\ensuremath{\sim}20\phantom{\rule{0.3em}{0ex}}\mathrm{meV}$, confirming a previous observation for $x=1∕3$. We discuss the possible origin of this gap.

We have investigated the spin dynamics in the strongly correlated chain copper oxide ${\mathrm{S}\mathrm{r}\mathrm{C}\mathrm{u}\mathrm{O}}_{2}$ for energies up to $\ensuremath{\gtrsim}0.6\text{ }\mathrm{e}\mathrm{V}$ using inelastic neutron scattering. We observe a gapless continuum of magnetic excitations, which is well described by the ``M\"uller ansatz'' for the two-spinon continuum in the $S=1/2$ antiferromagnetic Heisenberg spin chain. The lower boundary of the continuum extends up to $\ensuremath{\approx}360\text{ }\mathrm{m}\mathrm{e}\mathrm{V}$, which corresponds to an exchange constant $J=226(12)\text{ }\mathrm{m}\mathrm{e}\mathrm{V}$.

In the copper-oxide parent compounds of the high-transition-temperature superconductors, the valence electrons are localized, one per copper site, due to strong intraatomic Coulomb repulsion. A symptom of the localization is antiferromagnetism, where the spins of localized electrons alternate between up and down. The superconductivity appears when mobile 'holes' are doped into this insulating state, and it coexists with antiferromagnetic fluctuations. In one approach to the coexistence, the holes are believed to self-organize into 'stripes' that alternate with antiferromagnetic (insulating) regions within copper-oxide planes. Such an unusual electronic state would necessitate an unconventional mechanism of superconductivity. There is an apparent problem with this picture, however: measurements of magnetic excitations in superconducting YBa(2)Cu(3)O(6+x) near optimum doping are incompatible with the naive expectations for a material with stripes. Here we report neutron scattering measurements on stripe-ordered La(1.875)Ba(0.125)CuO(4). We show that the measured excitations are, surprisingly, quite similar to those in YBa(2)Cu(3)O(6+x) (i.e., the predicted spectrum of magnetic excitations is wrong). We find instead that the observed spectrum can be understood within a stripe model by taking account of quantum excitations. Our results support the concept that stripe correlations are essential to high-transition-temperature superconductivity., Comment: 11 pages, including 4 figures; revised version (rewritten abstract, text shortened, some changes to references, part of Fig. 4 eliminated)

S K and Ir ${L}_{3}$ x-ray absorption measurements across the temperature-induced metal (M) to insulator (I) transition in ${\mathrm{CuIr}}_{2}{\mathrm{S}}_{4}$ are presented. Dramatic S K-edge changes reflect the Ir d-electronic state redistribution across this transition. These changes, along with a detailed consideration of the I-phase structure, motivate a model in which the I-phase stabilization involves an interplay of charge and d-orbital orientation ordering along Ir chains, a quadrupling of the Ir-chain repeat unit, and correlated dimer spin-singlet formation.

The ${\mathrm{Bi}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$ system is known to exhibit charge ordering for a much broader range of x than the ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$ system. However, the properties of ${\mathrm{Bi}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$ over the entire doping range are not well understood. We have performed magnetization and resistivity measurements as well as x-ray absorption and x-ray diffraction measurements on ${\mathrm{Bi}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$ to correlate structural, magnetic, and transport properties. The system is insulating and antiferromagnetic for the entire range of x studied $(xg~0.4)$ except near $x\ensuremath{\sim}0.9,$ where we find a canted spin arrangement with approximately one Bohr magneton per Mn site. Detailed magnetization measurements were performed as a function of field and temperature to explore the net moment on the Mn sites as a function of x and reveal the charge ordering and N\'eel temperatures. X-ray absorption measurements reveal significant structural distortions of the Mn-O bond distributions with increasing Bi content that correlates directly with increasing charge-ordering temperatures. Moreover, the x-ray diffraction data reveal peak splittings consistent with lower-symmetry cells as Bi content increases. These structural-magnetic correlations point to the importance of Mn-O distortions in stabilizing the charge-ordered state in the manganites.

We report neutron scattering measurements of the spectrum of magnetic excitations in the stripe-ordered phase of La 2− x Sr x NiO 4 ( x =0.275 and 1 3 ). The propagating spin excitations follow a similar dispersion relation for the two compositions, but the line widths are broader for x =0.275 than for 1 3 .