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$B$-site ordered 4$d^1$ and 5$d^1$ double perovskites have a number of potential novel ground states including multipolar order, quantum spin liquids and valence bond glass states. These arise from the complex interactions of spin-orbital entangled $J_{eff}$ = 3/2 pseudospins on the geometrically frustrated fcc lattice. The 4$d^1$ Mo$^{5+}$ perovskite Ba$_2$YMoO$_6$ has been suggested to have a valence bond glass ground state. Here we report on the low temperature properties of powder samples of isostructural Ba$_2$LuMoO$_6$: the only other known cubic 4$d^1$ perovskite with one magnetic cation. Our muon spectroscopy experiments show that magnetism in this material remains dynamic down to 60 mK without any spin freezing or magnetic order. A singlet-triplet excitation with a gap of $\Delta$ = 28 meV is observed in inelastic neutron scattering. These results are interpreted as a disordered valence bond glass ground state similar to Ba$_2$YMoO$_6$. Our results highlight the differences of the 4$d^1$ double perovskites in comparison to cubic 5$d^1$ analogues, which have both magnetic and multipolar order., Comment: 23+4 pages, 5+5 figures

We introduce a simple method to extract the nuclear coherent and isotope incoherent, spin incoherent, and magnetic neutron scattering cross section components from powder scattering data measured using a single neutron beam polarization direction and a position-sensitive detector with large out-of-plane coverage. The method draws inspiration from polarized small-angle neutron scattering and contrasts with conventional so-called "xyz" polarization analysis on wide-angle instruments, which requires measurements with three orthogonal polarization directions. The viability of the method is demonstrated on both simulated and experimental data for the classical "spin ice" system Ho

Ruddlesden-Popper (RP) phases (An+1BnO3n+1, n = 1, 2,···) have attracted intensive research with diverse functionalities for device applications. However, the realization of a high-quality RP-phase film is hindered by the formation of out-of-phase boundaries (OPBs) that occur at terrace edges, originating from lattice mismatch in the c-axis direction with the A'B'O3 (n = ∞) substrate. Here, using strontium ruthenate RP-phase Sr2RuO4 (n = 1) as a model system, an experimental approach for suppressing OPBs was developed. By tuning the growth parameters, the Sr3Ru2O7 (n = 2) phase was formed in a controlled manner near the film-substrate interface. This higher-order RP-phase then blocked the subsequent formation of OPBs, resulting in nearly defect-free Sr2RuO4 layer at the upper region of the film. Consequently, the Sr2RuO4 thin films exhibited superconductivity up to 1.15 K, which is the highest among Sr2RuO4 films grown by pulsed laser deposition. This work paves the way for synthesizing pristine RP-phase heterostructures and exploring their unique physical properties.

Bismuth halides with formula A3Bi2X9, where A is an inorganic or organic cation, show desirable properties as solar absorbers and luminescent materials. Control of structural and electronic dimensionality of these compounds is important to yield materials with good light absorption and charge transport. Here we report mechanochemical reaction of (CH3NH3)3Bi2Br9 with SnBr2 at room temperature in air, yielding a material with strong absorption across the visible and near-infrared (NIR) region. We attribute this to mixed valence doping of Sn(II) and Sn(IV) on the Bi site. X-ray diffraction shows no secondary phases, even after heating at 200oC to improve crystallinity. X-ray photoelectron spectroscopy suggests the presence of Sn(II) and Sn(IV) states. A similar approach to dope Sn into the iodide analogue (CH3NH3)3Bi2I9 was unsuccessful.

Protected by the interplay of on-site Coulomb interactions and spin-orbit coupling, Sr$_2$IrO$_4$ at high pressure is a rare example of a Mott insulator with a paramagnetic ground state. Here, using optical Raman scattering, we measure both the phonon and magnon evolution in Sr$_2$IrO$_4$ under pressure, and identify three different magnetically-ordered phases, culminating in a spin-disordered state beyond 18 GPa. A strong first-order structural phase transition drives the magnetic evolution at $\sim$10 GPa with reduced structural anisotropy in the IrO$_6$ cages, leading to increasingly isotropic exchange interactions between the Heisenberg spins and a spin-flip transition to $c$-axis-aligned antiferromagnetic order. In the disordered phase of Heisenberg $J_\mathrm{eff}=1/2$ pseudospins, the spin excitations are quasi-elastic and continuous to 10 meV, potentially hosting a gapless quantum spin liquid in Sr$_2$IrO$_4$.

We introduce a simple method to extract the nuclear coherent and isotope incoherent, spin incoherent, and magnetic neutron scattering cross section components from powder scattering data measured using a single neutron beam polarization direction and a position-sensitive detector with large out-of-plane coverage. The method draws inspiration from polarized small-angle neutron scattering and contrasts with conventional so-called “ xyz” polarization analysis on wide-angle instruments, which requires measurements with three orthogonal polarization directions. The viability of the method is demonstrated on both simulated and experimental data for the classical “spin ice” system Ho2Ti2O7, the latter from the LET direct geometry spectrometer at the ISIS facility. The cross section components can be reproduced with good fidelity by either fitting the out-of-plane angle dependence around a Debye–Scherrer cone or grouping the data by angle and performing a matrix inversion. The limitations of the method and its practical uses are discussed.

Evidence for broken time reversal symmetry (TRS) has been found in the superconducting states of the ${R}_{5}{\mathrm{Rh}}_{6}{\mathrm{Sn}}_{18}$ ($R=\text{Sc}$, Y, Lu) compounds with a centrosymmetric caged crystal structure, but the origin of this phenomenon is unresolved. Here, we report neutron diffraction measurements of single crystals with $R=\text{Lu}$, as well as measurements of the temperature dependence of the magnetic penetration depth using a self-induced tunnel-diode-oscillator (TDO)-based technique, together with band structure calculations using density functional theory. Neutron diffraction measurements reveal that the system crystallizes in a tetragonal caged structure, and that one of the nominal Lu sites in the ${\mathrm{Lu}}_{5}{\mathrm{Rh}}_{6}{\mathrm{Sn}}_{18}$ structure is occupied by Sn, yielding a composition ${\mathrm{Lu}}_{5\ensuremath{-}x}{\mathrm{Rh}}_{6}{\mathrm{Sn}}_{18+x}$ ($x=1$). The low temperature penetration depth shift $\mathrm{\ensuremath{\Delta}}\ensuremath{\lambda}(T)$ exhibits an exponential temperature dependence below around $0.3{T}_{c}$, giving clear evidence for fully gapped superconductivity. The derived superfluid density is reasonably well accounted for by a single-gap $s$-wave model, whereas agreement cannot be found for models of TRS breaking states with two-component order parameters. Moreover, band structure calculations reveal multiple bands crossing the Fermi level, and indicate that the aforementioned TRS breaking states would be expected to have nodes on the Fermi surface, in contrast to the observations.

This work was supported by the UK-EPSRC under grant EP/G007357/1, by the Swiss National Science Foundation (SNSF) under grants 200020_165791 and 200020_184998, by the Max Planck Society, by the European Research Council (ERC StG SpinMelt), and by the Netherlands Organization for Scientific Research (NWO) under grants 680–47–536 and FOM-167. We acknowledge Diamond Light Source for time on beamline I05 under proposals no. SI13398 and SI5282. Discrepancies in the low-energy quasiparticle dispersion extracted from angle-resolved photoemission, scanning tunneling spectroscopy, and quantum oscillation data are common and have long haunted the field of quantum matter physics. Here, we directly test the consistency of results from these three techniques by comparing data from the correlated metal Sr2RhO4. Using established schemes for the interpretation of the experimental data, we find good agreement for the Fermi surface topography and carrier effective masses. Hence, the apparent absence of such an agreement in other quantum materials, including the cuprates, suggests that the electronic states in these materials are of different, non-Fermi liquid-like nature. Finally, we discuss the potential and challenges in extracting carrier lifetimes from photoemission and quasiparticle interference data. Publisher PDF

The quantum magnet SrCu2(BO3)2 is a physical realisation of the Shastry-Sutherland model - a two-dimensional square lattice, solved to have a ground state of singlets on diagonal bonds. Recent theoretical work suggests that the material should play host to a topological phase of triplons, which may manifest a thermal Hall effect. However, within the measured experimental resolution,we report that there is no thermal Hall signal of the predicted magnitude. This is possibly due to triplon-triplon interactions playing a more significant role than anticipated in the temperature range under investigation.

We have synthesized a single-crystalline sample of ${\mathrm{Mn}}_{2}{\mathrm{V}}_{2}{\mathrm{O}}_{7}$ using the floating zone technique, and we investigated the ground state using magnetic susceptibility, heat capacity, and neutron diffraction. Our magnetic susceptibility and heat capacity reveal two successive magnetic transitions at ${T}_{N1}=17\phantom{\rule{4pt}{0ex}}\mathrm{K}$ and ${T}_{N2}=11.8\phantom{\rule{4pt}{0ex}}\mathrm{K}$ indicating two distinct magnetically ordered phases. The single-crystal neutron diffraction study shows that in the temperature ($T$) range $11.8\ensuremath{\le}T\ensuremath{\le}17\phantom{\rule{4pt}{0ex}}\mathrm{K}$ the magnetic structure is commensurate with propagation vector ${k}_{1}=(0,0.5,0)$, while upon lowering temperature below ${T}_{N2}=11.8\phantom{\rule{4pt}{0ex}}\mathrm{K}$ an incommensurate magnetic order emerges with ${k}_{2}=(0.38,0.48,0.5)$ and the magnetic structure can be represented by cycloidal modulation of the Mn spin in the $ac$ plane. We discuss the role of magnetic exchange interactions and spin-orbital coupling on the stability of the observed magnetic phase transitions.

We study the magnetic structure of the 'stuffed' (Tb-rich) pyrochlore iridate Tb

We study the magnetic structure of the "stuffed" (Tb-rich) pyrochlore iridate Tb$_{2+x}$Ir$_{2-x}$O$_{7-y}$, using resonant elastic x-ray scattering (REXS). In order to disentangle contributions from Tb and Ir magnetic sublattices, experiments were performed at the Ir $L_3$ and Tb $M_5$ edges, which provide selective sensitivity to Ir $5d$ and Tb $4f$ magnetic moments, respectively. At the Ir $L_3$ edge, we found the onset of long-range ${\bf k}={\bf 0}$ magnetic order below $T_{N}^\text{Ir}\sim$ 71 K, consistent with the expected signal of all-in all-out (AIAO) magnetic order. Using a single-ion model to calculate REXS cross-sections, we estimate an ordered magnetic moment of $\mu_{5d}^{\text{Ir}} \approx 0.34(3)\,\mu_B$ at 5 K. At the Tb $M_5$ edge, long-range ${\bf k}={\bf 0}$ magnetic order appeared below $\sim40$ K, also consistent with an AIAO magnetic structure on the Tb site. Additional insight into the magnetism of the Tb sublattice is gleaned from measurements at the $M_5$ edge in applied magnetic fields up to 6 T, which is found to completely suppress the Tb AIAO magnetic order. In zero applied field, the observed gradual onset of the Tb sublattice magnetisation with temperature suggests that it is induced by the magnetic order on the Ir site. The persistence of AIAO magnetic order, despite the greatly reduced ordering temperature and moment size compared to stoichiometric Tb$_{2}$Ir$_{2}$O$_{7}$, for which $T_{N}^{\text{Ir}} =130$ K and $\mu_{5d}^{\text{Ir}}=0.56\,\mu_B$, indicates that stuffing could be a viable means of tuning the strength of electronic correlations, thereby potentially offering a new strategy to achieve topologically non-trivial band crossings in pyrochlore iridates., Comment: 9 pages, 6 figures

X-ray magnetic critical scattering measurements and specific heat measurements were performed on the perovskite iridate [Formula: see text]. We find that the magnetic interactions close to the Néel temperature [Formula: see text] are three-dimensional. This contrasts with previous studies which suggest two-dimensional behaviour like Sr

Magnetic materials are a cornerstone for developing spintronic devices for the transport of information via magnetic excitations. To date, relatively few materials have been investigated for the purpose of spin transport, mostly due to the paucity of suitable candidates as these materials are often chemically complex and difficult to synthesize. We present the crystal growth and a structure solution on the high-temperature crystal structure of the layered, polar ferrimagnet ${\mathrm{CaBaFe}}_{4}{\mathrm{O}}_{7}$, which is a possible new contender for spintronics research. The space group is identified as $P3$ by refinement of single crystal and powder neutron diffraction data. At 400 K, the trigonal lattice parameters are $a=11.0114(11)\phantom{\rule{4pt}{0ex}}\AA{}$ and $c=10.330(3)\phantom{\rule{4pt}{0ex}}\AA{}$. The structure is similar to the low-temperature phase with alternating layers of triangular and Kagome-arranged Fe-O tetrahedra. We also present details of the crystal growth by traveling solvent method.

Resonant inelastic X-ray scattering (RIXS) experiments performed at the oxygen-$K$ edge on the iridate perovskites {\SIOS} and {\SION} reveal a sequence of well-defined dispersive modes over the energy range up to $\sim 0.8$ eV. The momentum dependence of these modes and their variation with the experimental geometry allows us to assign each of them to specific collective magnetic and/or electronic excitation processes, including single and bi-magnons, and spin-orbit and electron-hole excitons. We thus demonstrated that dispersive magnetic and electronic excitations are observable at the O-$K$ edge in the presence of the strong spin-orbit coupling in the $5d$ shell of iridium and strong hybridization between Ir $5d$ and O $2p$ orbitals, which confirm and expand theoretical expectations. More generally, our results establish the utility of O-$K$ edge RIXS for studying the collective excitations in a range of $5d$ materials that are attracting increasing attention due to their novel magnetic and electronic properties. Especially, the strong RIXS response at O-$K$ edge opens up the opportunity for investigating collective excitations in thin films and heterostructures fabricated from these materials., Comment: 6 pages, 4 figures with supplementary material. Accepted by PRB Rapid Communications

Magnetic spinels (with chemical formula $A{X}_{2}{\mathrm{O}}_{4}$, with $X$ a $3d$ transition metal ion) that also have an orbital degeneracy are Jahn-Teller active and hence possess a coupling between spin and lattice degrees of freedom. At high temperatures, ${\mathrm{MgV}}_{2}{\mathrm{O}}_{4}$ is a cubic spinel based on ${\mathrm{V}}^{3+}$ ions with a spin $S=1$ and a triply degenerate orbital ground state. A structural transition occurs at ${T}_{\text{OO}}=63$ K to an orbitally ordered phase with a tetragonal unit cell followed by an antiferromagnetic transition of ${T}_{N}=42$ K on cooling. We apply neutron spectroscopy in single crystals of ${\mathrm{MgV}}_{2}{\mathrm{O}}_{4}$ to show an anomaly for intermediate wave vectors at ${T}_{\text{OO}}$ associated with the acoustic phonon sensitive to the shear elastic modulus $\left({C}_{11}\ensuremath{-}{C}_{12}\right)/2$. On warming, the shear mode softens for momentum transfers near close to half the Brillouin zone boundary, but recovers near the zone center. High resolution spin-echo measurements further illustrate a temporal broadening with increased temperature over this intermediate range of wave vectors, indicative of a reduction in phonon lifetime. A subtle shift in phonon frequencies over the same range of momentum transfers is observed with magnetic fields. We discuss this acoustic anomaly in context of coupling to orbital and charge fluctuations.

We study the structural evolution of Sr3Ir2O7 as a function of pressure using x-ray diffraction. At a pressure of 54 GPa at room temperature, we observe a first-order structural phase transition, associated with a change from tetragonal to monoclinic symmetry and accompanied by a 4% volume collapse. Rietveld refinement of the high-pressure phase reveals a novel modification of the Ruddlesden-Popper structure, which adopts an altered stacking sequence of the perovskite bilayers. As the positions of the oxygen atoms could not be reliably refined from the data, we use density functional theory (local-density approximation+U+spin orbit) to optimize the crystal structure and to elucidate the electronic and magnetic properties of Sr3Ir2O7 at high pressure. In the low-pressure tetragonal phase, we find that the in-plane rotation of the IrO6 octahedra increases with pressure. The calculations further indicate that a bandwidth-driven insulator-metal transition occurs at ∼20 GPa, along with a quenching of the magnetic moment. In the high-pressure monoclinic phase, structural optimization resulted in complex tilting and rotation of the oxygen octahedra and strongly overlapping t2g and eg bands. The t2g bandwidth renders both the spin-orbit coupling and electronic correlations ineffectual in opening an electronic gap, resulting in a robust metallic state for the high-pressure phase of Sr3Ir2O7.

Bilayer strontium ruthenate Sr_{3}Ru_{2}O_{7} displays pronounced non-Fermi liquid behavior at magnetic fields around 8 T, applied perpendicular to the ruthenate planes, which previously has been associated with an itinerant metamagnetic quantum critical end point (QCEP). We focus on the magnetic Grüneisen parameter Γ_{H}, which is the most direct probe to characterize field-induced quantum criticality. We confirm quantum critical scaling due to a putative two-dimensional QCEP near 7.845(5) T, which is masked by two ordered phases A and B, identified previously by neutron scattering. In addition, we find evidence for a QCEP at 7.53(2) T and determine the quantum critical regimes of both instabilities and the effect of their superposition.

The magnetic excitation spectrum in the bilayer iridate Sr3Ir2O7 has been investigated using high-resolution resonant inelastic x-ray scattering (RIXS) performed at the iridium L-3 edge and theoretical techniques. A study of the systematic dependence of the RIXS spectrum on the orientation of the wave-vector transfer Q, with respect to the iridium-oxide bilayer, has revealed that the magnon dispersion is comprised of two branches well separated in energy and gapped across the entire Brillouin zone. Our results contrast with those of an earlier study which reported the existence of a single dominant branch. While these earlier results were interpreted as two overlapping modes within a spin-wave model of weakly coupled iridium-oxide planes, our results are more reminiscent of those expected for a system of weakly coupled dimers. In this latter approach, the lower-and higher-energy modes find a natural explanation as those corresponding to transverse and longitudinal fluctuations, respectively. We have therefore developed a bond-operator theory which describes the magnetic dispersion in Sr3Ir2O7 in terms of quantum dimer excitations. In our model, dimerization is produced by the leading Heisenberg exchange J(c), which couples iridium ions in adjacent planes of the bilayer. The Hamiltonian also includes in-plane exchange J, as well as further neighbor couplings and relevant anisotropies. The bond-operator theory provides an excellent account of the dispersion of both modes, while the measured Q dependence of the RIXS intensities is in reasonable qualitative accord with the spin-spin correlation function calculated from the theory. We discuss our results in the context of the quantum criticality of bilayer dimer systems in the presence of anisotropic interactions derived from strong spin-orbit coupling.

The conduction electrons in a metal experience competing interactions with each other and the atomic nuclei. This competition can lead to many types of magnetic order in metals. For example, in chromium the electrons order to form a spin-density-wave (SDW) antiferromagnetic state. A magnetic field may be used to perturb or tune materials with delicately balanced electronic interactions. Here we show that the application of a magnetic field can induce SDW magnetic order in a metal, where none exists in the absence of the field. We use magnetic neutron scattering to show that the application of a large (~8T) magnetic field to the metamagnetic perovskite metal Sr3Ru2O7 can be used to tune the material through two magnetically-ordered SDW states. The ordered states exist over relatively small ranges in field (, Legend in Fig. 3(b) corrected

Neutron inelastic scattering has been used to probe the spin dynamics of the quantum (S=1/2) ferromagnet on the pyrochlore lattice Lu(2)V(2)O(7). Well-defined spin waves are observed at all energies and wave vectors, allowing us to determine the parameters of the Hamiltonian of the system. The data are found to be in excellent overall agreement with a minimal model that includes a nearest-neighbor Heisenberg exchange J = 8.22(2) meV and a Dzyaloshinskii-Moriya interaction (DMI) D = 1.5(1) meV. The large DMI term revealed by our study is broadly consistent with the model originally used to explain the magnon Hall effect in this compound [Onose et al., Science 329, 297 (2010) and Ideue et al., Phys. Rev. B 85, 134411 (2012)]. However, our ratio of D/J = 0.18(1) is roughly half of their value, and is much larger than those found in other theoretical studies [Xiang et al., Phys. Rev. B 83, 174402 (2011) and Mook et al., Phys. Rev. B 89,134409 (2014)].

Sr2IrO4 is a prototype of the class of Mott insulators in the strong spin-orbit interaction (SOI) limit described by a Jeff = 1/2 ground state. In Sr2IrO4, the strong SOI is predicted to manifest itself in the locking of the canting of the magnetic moments to the correlated rotation by 11.8(1)° of the oxygen octahedra that characterizes its distorted layered perovskite structure. Using x-ray resonant scattering at the Ir L3 edge we have measured accurately the intensities of Bragg peaks arising from different components of the magnetic structure. From a careful comparison of integrated intensities of peaks due to basal-plane antiferromagnetism, with those due to b-axis ferromagnetism, we deduce a canting of the magnetic moments of 12.2(8)°. We thus confirm that in Sr2IrO4 the magnetic moments rigidly follow the rotation of the oxygen octahedra, indicating that, even in the presence of significant non-cubic structural distortions, it is a close realization of the Jeff = 1/2 state.

The phase diagram of Sr3Ru2O7 shows hallmarks of strong electron correlations despite the modest Coulomb interaction in the Ru 4d shell. We use angle-resolved photoelectron spectroscopy measurements to provide microscopic insight into the formation of the strongly renormalized heavy d-electron liquid that controls the physics of Sr3Ru2O7. Our data reveal itinerant Ru 4d-states confined over large parts of the Brillouin zone to an energy range of

Sr2IrO4 is a prototype of the class of Mott insulators in the strong spin-orbit interaction (SOI) limit described by a $J_{\mathrm{eff}}=1/2$ ground state. In Sr2IrO4, the strong SOI is predicted to manifest itself in the slaving of the canting of the magnetic moments to the correlated rotation by 11.8(1)$^{\circ}$ of the oxygen octahedra that characterizes its distorted layered perovskite structure. Using X-ray resonant scattering at the Ir $L_3$ edge we have measured accurately the intensities of Bragg peaks arising from different components of the magnetic structure. From a careful comparison of integrated intensities of peaks due to basal-plane antiferromagnetism, with those due to b-axis ferromagnetism, we deduce a canting of the magnetic moments of 12.2(8)$^{\circ}$. We thus confirm that in Sr2IrO4 the magnetic moments rigidly follow the rotation of the oxygen octahedra, indicating that, even in the presence of significant non-cubic structural distortions, it is a close realization of the $J_{\mathrm{eff}}=1/2$ state

The objective of this experiment was to assess the efficacy of insecticides currently labeled for use on cranberry (Altacor, Delegate, Intrepid, Confirm), softer chemistry insecticides labeled on cranberry (Grandevo and Venerate), and insecticides not currently labeled on cranberry (cyclaniliprole, Fanfare, and Exirel). Selected insecticides were applied with and without the addition of the non-ionic adjuvant Apsa (spreader/activator) on first generation CFW and SFW eggs and early instar larvae. This experiment was conducted in a 4-yr-old cranberry planting on a commercial farm near Plainfield, WI. The trial consisted of 17 main effect treatments arranged in a complete randomized block design with 4 experimental replicates. Each …

This experiment aimed at assessing the efficacy of insecticides currently labeled for use in cranberry (Altacor, Diazinon, and Orthene), softer chemistry insecticides labeled on cranberry (Grandevo and Venerate), and insecticides not currently labeled on cranberry (cyclaniliprole, Fanfare, and Exirel) on second generation of BHFW larvae and on CEM larvae (univoltine). This experiment was conducted in a mature cranberry planting on a commercial farm near Warrens, Wisconsin. The trial consisted of 12 main effect treatments arranged in a Complete Randomized Block design with four experimental replicates. Each replicate plot was 10 × 25 ft. Foliar applications of these …

The objective of this experiment was to assess the efficacy of adding the nonionic adjuvant Apsa (spreader/activator) to a late foliar application of an insecticide currently labeled for use in cranberry (Altacor) and insecticides not currently labeled on cranberry (Bifenthrin, Cyclaniliprole, and Exirel) on cranberry flea beetle (CFB). This experiment was conducted in a mature cranberry planting on a commercial farm near Warrens, Wisconsin. The trial consisted of 13 main effect treatments arranged in a Complete Randomized Block design with four experimental replicates. Each replicate plot was 7 × 10 ft. …

In the summer 2015, an experiment was conducted to assess the efficacy of insecticides currently labeled for use in cranberry (Altacor, Diazinon, Assail, and Orthene), a registered insect growth regulator (Rimon), softer chemistry insecticides labeled on cranberry (Grandevo and Venerate), and insecticides not currently labeled on cranberry (cyclaniliprole, Closer, Fanfare, Movento, and Exirel) on cranberry tipworm. This experiment was conducted in a mature cranberry planting on a commercial farm near Warrens, Wisconsin. The trial consisted of 13 main effect treatments arranged in an RCB …

In the summer of 2015, we conducted an experiment to assess the efficacy of an early foliar application of insecticides currently labeled for use in cranberry (Altacor, Assail, Actara, Belay, Diazinon, Imidan, and Lorsban) and insecticides not currently labeled on cranberry (Bifenthrin, Closer, a diamide, Exirel, Movento, and Venom) on cranberry flea beetle. This experiment was conducted in a 4-year-old cranberry planting on a commercial farm near Oakdale, Wisconsin. The trial consisted …

The objective of this experiment was to assess the efficacy of insecticides currently labeled for use in cranberry (Fanfare, Altacor, Diazinon, Belay, Knack, Assail, Delegate, Imidan, Rimon, Lorsban, Venom, Intrepid, Closer), softer chemistry insecticides labeled on cranberry (Grandevo and Venerate), and insecticides not currently labeled on cranberry (Movento and Exirel) on cranberry tipworm. This experiment was conducted in a mature cranberry planting on a commercial farm near Warrens, Wisconsin. The trial consisted of 18 main effect treatments …

The objective of this experiment was to assess the efficacy on second generation of BHFW larvae of insecticides currently labeled for use in cranberry (Fanfare, Altacor, Diazinon, Belay, Knack, Assail, Delegate, Imidan, Rimon, Lorsban, Venom, Intrepid, and Closer), softer chemistry insecticides labeled on cranberry (Grandevo and Venerate), and insecticides not currently labeled on cranberry (Movento and Exirel). This experiment was conducted in a mature cranberry planting on a commercial farm near Byron, Wisconsin. The …

The objective of this experiment was to assess the efficacy of insecticides currently labeled for use in cranberry (Altacor, Delegate, Intrepid, Confirm), softer chemistry insecticides labeled on cranberry (Grandevo and Venerate), and an insecticide not currently labeled on cranberry (Exirel) in combination with the adjuvant Bond (spreader/sticker) on first generation CFW and SFW eggs and larvae. This experiment was conducted in a mature cranberry planting on a commercial farm near Warrens, Wisconsin. The trial consisted of 14 main effect treatments arranged in an RCB design with four experimental replicates. Each …

The behavior of matter near zero temperature continuous phase transitions, or "quantum critical points" is a central topic of study in condensed matter physics. In fermionic systems, fundamental questions remain unanswered: the nature of the quantum critical regime is unclear because of the apparent breakdown of the concept of the quasiparticle, a cornerstone of existing theories of strongly interacting metals. Even less is known experimentally about the formation of ordered phases from such a quantum critical "soup." Here, we report a study of the specific heat across the phase diagram of the model system Sr 3Ru 2O 7, which features an anomalous phase whose transport properties are consistent with those of an electronic nematic. We show that this phase, which exists at low temperatures in a narrow range of magnetic fields, forms directly from a quantum critical state, and contains more entropy than mean-field calculations predict. Our results suggest that this extra entropy is due to remnant degrees of freedom from the highly entropic state above T c . The associated quantum critical point, which is "concealed" by the nematic phase, separates two Fermi liquids, neither of which has an identifiable spontaneously broken symmetry, but which likely differ in the topology of their Fermi surfaces., Instituto de Física de Líquidos y Sistemas Biológicos

The electronic nematic phase of Sr₃Ru₂O₇ is investigated by high-resolution in-plane thermal expansion measurements in magnetic fields close to 8 T applied at various angles Θ off the c axis. At Θ10° we observe a very small (10⁻⁷) lattice distortion which breaks the fourfold in-plane symmetry, resulting in nematic domains with interchanged a and b axis. At Θ ≳ 10° the domains are almost fully aligned and thermal expansion indicates an area-preserving lattice distortion of order 2 × 10⁻⁶ which is likely related to orbital ordering. Since the system is located in the immediate vicinity of a metamagnetic quantum critical end point, the results represent the first observation of a structural relaxation driven by quantum criticality.

We report measurements of quantum oscillations detected in the putative nematic phase of Sr3Ru2O7. Improvements in sample purity enabled the resolution of small amplitude de Haas-van Alphen (dHvA) oscillations between two first order metamagnetic transitions delimiting the phase. Two distinct frequencies were observed, whose amplitudes follow the normal Lifshitz-Kosevich profile. Variations of the dHvA frequencies are explained in terms of a chemical potential shift produced by reaching a peak in the density of states, and an anomalous field dependence of the oscillatory amplitude provides information on domains.

The low-energy electronic structure of the itinerant metamagnet Sr3Ru2O7 is investigated by angle-resolved photoemission and density-functional calculations. We find well-defined quasiparticle bands with resolution-limited linewidths and Fermi velocities up to an order of magnitude lower than in single layer Sr2RuO4. The complete topography, the cyclotron masses, and the orbital character of the Fermi surface are determined, in agreement with bulk sensitive de Haas-van Alphen measurements. An analysis of the dxy band dispersion reveals a complex density of states with van Hove singularities near the Fermi level, a situation which is favorable for magnetic instabilities.

We report critical current measurements of the ${\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}\text{\ensuremath{-}}{\mathrm{Sr}}_{3}{\mathrm{Ru}}_{2}{\mathrm{O}}_{7}$ eutectic system, a solid mixture of the spin-triplet superconductor ${\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}$ and the nearly ferromagnetic metal ${\mathrm{Sr}}_{3}{\mathrm{Ru}}_{2}{\mathrm{O}}_{7}$. Our results reveal that this eutectic forms an unusual superconducting state with features distinct from those of the pure ${\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}$ phase. We observe a crossover from Ambegaokar-Baratoff to Ginzburg-Landau type behavior in the temperature dependence of the critical current, similar to the behavior of Josephson weak-link networks in granular high-${T}_{c}$ cuprates. Our results suggest that large regions of ${\mathrm{Sr}}_{3}{\mathrm{Ru}}_{2}{\mathrm{O}}_{7}$ in this solid mixture may become superconducting by an unusual proximity effect.

High-resolution angular resolved photoemission data reveal well-defined quasiparticle bands of unusually low weight, emerging in line with the metallic phase of Ca(3)Ru(2)O(7) below approximately 30 K . At the bulk structural phase transition temperature of 48 K, we find clear evidence for an electronic instability, gapping large parts of the underlying Fermi surface that appears to be nested. Metallic pockets are found to survive in the small, non-nested sections, constituting a low-temperature Fermi surface with 2 orders of magnitude smaller volume than in all other metallic ruthenates. The Fermi velocities and volumes of these pockets are in agreement with the results of complementary quantum oscillation measurements on the same crystal batches.

Thermal conductivity of Sr3Ru2O7 was measured down to 40 mK and at magnetic fields through the quantum critical end point at Hc=7.85 T. A peak in the electrical resistivity as a function of the field was mimicked by the thermal resistivity. In the limit as T--0 K, we find that the Wiedemann-Franz law is satisfied to within 5% at all fields, implying that there is no breakdown of the electron despite the destruction of the Fermi liquid state at quantum criticality. A significant change in disorder [from rho0(H=0 T)=2.1 to 0.5 microOmega cm] does not influence our conclusions. At finite temperatures, the temperature dependence of the Lorenz number is consistent with ferromagnetic fluctuations causing the non-Fermi liquid behavior as one would expect at a metamagnetic quantum critical end point.

We report low-temperature thermal expansion measurements on the bilayer ruthenate Sr3Ru2O7 as a function of magnetic field applied perpendicular to the ruthenium-oxide planes. The field dependence of the c-axis expansion coefficient indicates the accumulation of entropy close to 8 T, related to an underlying quantum critical point. The latter is masked by two first-order metamagnetic transitions which bound a regime of enhanced entropy. Outside this region the singular thermal expansion behavior is compatible with the predictions of the itinerant theory for a two-dimensional metamagnetic quantum critical end point.