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Pesticide lifecycle management encompasses a range of elements from legislation, regulation, manufacturing, application, risk reduction, monitoring, and enforcement to disposal of pesticide waste. A survey was conducted in 2017–2018 to describe the contemporary global status of pesticide lifecycle management, to identify where the gaps are found. A three-tiered questionnaire was distributed to government entities in 194 countries. The response rate was 29%, 27% and 48% to the first, second and third part of the questionnaire, respectively. The results showed gaps for most of the selected indicators of pesticide management, suggesting that pesticide efficacy and safety to human health and the environment are likely being compromised at various stages of the pesticide lifecycle, and at varying degrees across the globe. Low-income countries generally had the highest incidence of gaps. Particular shortcomings were deficiencies in pesticide legislation, inadequate capacity for pesticide registration, protection against occupational exposure to pesticides, consumer protection against residues in food, and environmental protection against pesticide contamination. Policy support for, and implementation of, pesticide use-reduction strategies such as integrated pest management and integrated vector management has been inadequate across regions. Priority actions for structural improvement in pesticide lifecycle management are proposed, including pesticide use-reduction strategies, targeted interventions, and resource mobilization., Graphical abstract Unlabelled Image, Highlights • Gaps in lifecycle management of agriculture and public health pesticides were common. • Low-income countries had most gaps, affecting pesticide efficacy and safety. • Pesticide legislation and registration showed shortcomings in most countries. • Inadequate measures against pesticide exposure and contamination were a concern. • To reduce pesticide use, IPM and IVM should be prioritized in international policy.

We review a selection of recent applications of neutron scattering to the field of quantum magnetism. We focus on systems where, because of quantum fluctuations enhanced by frustration and low dimension, there is no long range magnetic order in the ground state. We select two examples that we treat in more depth to show how neutron studies, in conjunction with the results of other experimental techniques, can give new insights. The first is the case of the spin ladder NaV2O5, where the origin of the spin gap at low temperature is now understood in detail. Apparent contradictions between quantitative measures of the charge order from neutron inelastic scattering, resonant X-ray scattering and NMR have been resolved giving interesting insights into the correlations. The second case is that of spin dimer system Cs3Cr2 X 9 (X= Br, Cl), undergoing transitions to field induced transverse magnetic order. The Br compound is attractive as the critical fields are sufficiently low that a complete study, in different field directions, is possible. In addition, it is noteworthy in that the magnon that softens and condenses is incommensurable with the lattice. The common description in terms of Bose–Einstein condensation must be extended to include a continuous degeneracy and single ion anisotropy, and conclusions can be drawn by comparison with the Cl compound. To cite this article: B. Grenier, T. Ziman, C. R. Physique 8 (2007).

We have studied the spin correlations with $\bf{k}$= ($\frac12$, $\frac12$, $\frac12$) propagation vector which appear below 0.4\, K in \tbti\ spin liquid by combining powder neutron diffraction and specific heat on Tb$_{2+x}$Ti$_{2-x}$O$_{7+y}$ samples with $x$=0, 0.01, -0.01. The $\bf{k}$= ($\frac12$, $\frac12$, $\frac12$) order clearly appears on all neutron patterns by subtracting a pattern at 1.2(1)\,K. Refining the subtracted patterns at 0.07\,K yields two possible spin structures, with spin-ice-like and monopole-like correlations respectively. Mesoscopic correlations involve Tb moments of 1 to 2 \mub\ ordered on a length scale of about 20 \AA. In addition, long range order involving a small spin component of 0.1 to 0.2 \mub\ is detected for the $x$= 0 and 0.01 samples showing a peak in the specific heat. Comparison with previous single crystals data suggests that the ($\frac12$, $\frac12$, $\frac12$) order settles in through nanometric spin textures with dominant spin ice character and correlated orientations, analogous to nanomagnetic twins.

In UGe2, ZrZn2 and URhGe the co-existence of superconductivity and ferromagnetism appears to arise as a co-operative phenomena rather than as the overlap of two mutually competing orders. In all three compounds the magnetism is in intimate contact with the electronic degrees of freedom while the Curie temperatures are more than an order of magnitude higher than their critical temperatures for superconductivity. The most direct indication that the two orders are conjugate however is that the superconductivity and ferromagnetism are suppressed at the same critical pressure in both UGe2 and ZrZn2. This has motivated the recent theoretical classification of the permitted superconducting order parameter symmetries for such states. In the following we will review the experimental evidence relevant to the identification of the actual symmetries. This is followed by a discussion of the possible states allowed theoretically. Finally we discuss briefly whether the magnetic order can indeed lead to an enhancement of the superconductivity.

Recently superconductivity has been observed in two different 5f-electron ferromagnets, UGe2 and URhGe, well below their Curie temperatures. While superconductivity could be generic to all clean ferromagnets an alternative possibility is that it occurs in these materials, which were after all carefully selected for study, due to some special features related to the participation of strongly correlated 5f electrons in the ferromagnetism. 5f electrons potentially give rise to strong anisotropies, strong spin–orbit interactions and also a strong energy dependence of the electronic density of states. Here we focus on UGe2, and review several of the properties of the ferromagnetic state that could be a consequence of such features and discuss whether they promote superconductivity.

Er${}_{2}$Ti${}_{2}$O${}_{7}$ is believed to be a realization of an $\mathit{XY}$ antiferromagnet on a frustrated lattice of corner-sharing regular tetrahedra. It is presented as an example of the order-by-disorder mechanism in which fluctuations lift the degeneracy of the ground state, leading to an ordered state. Here we report detailed measurements of the low-temperature magnetic properties of Er${}_{2}$Ti${}_{2}$O${}_{7}$, which displays a second-order phase transition at ${T}_{\mathrm{N}}\ensuremath{\simeq}1.2$ K with coexisting short- and long-range orders. Magnetic susceptibility studies show that there is no spin-glass-like irreversible effect. Heat capacity measurements reveal that the paramagnetic critical exponent is typical of a 3-dimensional $\mathit{XY}$ magnet while the low-temperature specific heat sets an upper limit on the possible spin-gap value and provides an estimate for the spin-wave velocity. Muon spin relaxation measurements show the presence of spin dynamics in the nanosecond time scale down to 21 mK. This time range is intermediate between the shorter time characterizing the spin dynamics in Tb${}_{2}$Sn${}_{2}$O${}_{7}$, which also displays long- and short-range magnetic order, and the time scale typical of conventional magnets. Hence the ground state is characterized by exotic spin dynamics. We determine the parameters of a symmetry-dictated Hamiltonian restricted to the spins in a tetrahedron, by fitting the paramagnetic diffuse neutron scattering intensity for two reciprocal lattice planes. These data are recorded in a temperature region where the assumption that the correlations are limited to nearest neighbors is fair.

The temperature and magnetic field dependence of the magnetic structure in the singlet crystal-field ground-state system ${\text{PrNi}}_{2}{\text{Si}}_{2}$ have been determined using single-crystal neutron diffraction. At the magnetic ordering temperature in zero field, ${T}_{N}=20.0\ifmmode\pm\else\textpm\fi{}0.5\text{ }\text{K}$, an amplitude-modulated magnetic structure sets in with a propagation vector $\mathbf{k}=(0,0,0.87)$ and the magnetic moments of the ${\text{Pr}}^{3+}$ ions parallel to the $c$ axis of the body-centered tetragonal structure. The magnetic structure remains amplitude modulated down to low temperatures $(T=1.6\text{ }\text{K})$ with only a small tendency to squaring up, as signaled by the weak intensity of the third harmonic that develops below 16 K. With applied field along the easy axis, the modulated structure goes smoothly over into a ferromagnetic state. At the critical field of ${H}_{c}=58\text{ }\text{kOe}$, the first harmonic disappears and the field-induced ferromagnetic moment shows a kink, in agreement with magnetization measurements. Both the temperature and magnetic field dependence are well described by a periodic field Hamiltonian including magnetic exchange and the crystalline electric field.

The chemical selectivity and great sensitivity of the Extended X-ray Absorption Spectroscopy technique allowed the determination, in the paramagnetic phase, of the structural distortions induced by doping in the spin-Peierls CuGeO$_3$ compound. The distorted environments were analyzed as a function of concentration, magnetic nature of impurity and the substitution site (Ni, Mn and Zn impurities on the Cu site, Si impurity on the Ge site). This has led to estimate the variation of the angles and pair distances, and hence to evaluate the magnetic coupling along the Cu chains in the vicinity of the impurities. The antiferromagnetic interaction between Cu first neighbors in the pure sample is found to be weakened around Ni, almost cancelled in the case of Mn doping, and even to change sign, producing a ferromagnetic coupling for Si doping. More generally, the structural distortions on a local scale are shown to be key parameters for the understanding of the magnetic properties of doped spin-Peierls compounds.

We report that the flux-line lattice in the cubic superconductor Pr(Os4Sb12 is strongly distorted from an ideal hexagonal lattice at very low temperatures in a small applied field. We attribute this to the presence of gap nodes in the superconducting state on at least some Fermi-surface sheets.

We have performed electron-spin-resonance measurements on single crystals of the doped spin-Peierls compounds ${\mathrm{CuGe}}_{1\ensuremath{-}y}{\mathrm{Si}}_{y}{\mathrm{O}}_{3}$ and ${\mathrm{Cu}}_{1\ensuremath{-}x}{M}_{x}{\mathrm{GeO}}_{3}$ with $M=\mathrm{Zn},$ Mg, Ni $(x,yl~0.1).$ The first part of our experiments was performed in the paramagnetic and spin-Peierls phases at 9.5, 95, and 190 GHz. All nonmagnetic impurities (Si, Zn and Mg) were found to hardly affect the position and linewidth of the single line resonance, in spite of the moment formation due to the broken chains. In contrast to Si, Zn, and Mg dopings, the presence of Ni $(S=1)$ at low concentration induces a spectacular shift toward high fields of the ESR line (up to 40% for $x=0.002),$ together with a large broadening. This shift is strictly proportional to the ratio of Ni to Cu susceptibilities: Hence it is strongly enhanced below the spin-Peierls transition. We interpret this shift and the broadening as due to the exchange field induced by the Ni ions onto strongly exchange coupled Cu spins. Second, the antiferromagnetic resonance was investigated in Ni-doped samples. The frequency vs magnetic-field relation of the resonance is well explained by the classical theory with orthorhombic anisotropy, with g values remarkably reduced, in accordance with the study of the spin-Peierls and paramagnetic phases. The easy, second-easy, and hard axes are found to be a, c, and b axes, respectively. These results, which are dominated by the single ion anisotropy of ${\mathrm{Ni}}^{2+},$ are discussed in comparison with those in the Zn- and Si-doped ${\mathrm{CuGeO}}_{3}.$

We investigate magnetic properties of an $S$=1/2 quasi-one dimensional organic antiferromagnet, D-F$_{5}$PNN using magnetization measurements taken at temperatures as low as 0.5 K. Three distinct phases were observed consisting of uniform, dimerized (D), and incommensurate (I) spin structures in the magnetic field versus temperature plane, where a significant hysteresis appears between D-I transitions in the field scan measurements. A combination of magnon ($S$=1) and soliton ($S$=1/2) excitations have successfully reproduced the observed magnetic susceptibility. In addition, such excitations provide a reasonable interpretation of the temperature dependent electron spin resonance (ESR) spectra. By comparison with the theoretical study, we conclude that D-F$_{5}$PNN is an ideal compound for investigating the spin-Peierls transition.