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Altering the composition of the spacer layers present in iron-based superconductors is one strategy for increasing the temperature below which they superconduct. Now, intercalating FeSe with molecular spacer layers is also shown to enhance the superconducting transition temperature. The discovery of high-temperature superconductivity in a layered iron arsenide 1 has led to an intensive search to optimize the superconducting properties of iron-based superconductors by changing the chemical composition of the spacer layer between adjacent anionic iron arsenide layers 2 , 3 , 4 , 5 , 6 , 7 . Superconductivity has been found in iron arsenides with cationic spacer layers consisting of metal ions (for example, Li + , Na + , K + , Ba 2+ ) or PbO- or perovskite-type oxide layers, and also in Fe 1.01 Se (ref.  8 ) with neutral layers similar in structure to those found in the iron arsenides and no spacer layer. Here we demonstrate the synthesis of Li x (NH 2 ) y (NH 3 ) 1− y Fe 2 Se 2  ( x ~0.6; y ~0.2), with lithium ions, lithium amide and ammonia acting as the spacer layer between FeSe layers, which exhibits superconductivity at 43(1) K, higher than in any FeSe-derived compound reported so far. We have determined the crystal structure using neutron powder diffraction and used magnetometry and muon-spin rotation data to determine the superconducting properties. This new synthetic route opens up the possibility of further exploitation of related molecular intercalations in this and other systems to greatly optimize the superconducting properties in this family.

Climate change impacts require us to reexamine crop growth and yield under increasing temperatures and continuing yearly climate variability. Agronomic and agro-meteorological variables were concorded for a large number of plantings of green bean ( Phaseolus vulgaris L.) in three growing seasons over several years from semi-tropical Queensland. Using the Queensland government’s SILO meteorological database matched to sowing dates and crop phenology, we derived planting specific agro-meteorological variables. Linear and nonlinear statistical models were used to predict duration of vegetative and pod filling periods and fresh yield using agro-meteorological variables including thermal time, radiation and days of high temperature stress. High temperatures over 27.5∘C and 30∘C in the pod fill period were associated with a lower fresh bean yield. Differences between specific bean growing sites were examined using our bespoke open source software to derive agro-meteorological variables. Agronomically informed statistical models using production data were useful in predicting time of harvest. These methods can be applied to other commercial crops when crop phenology dates are collected.

Solid-state batteries are a proposed route to safely achieving high energy densities, yet this architecture faces challenges arising from interfacial issues between the electrode and solid electrolyte. Here we develop a novel family of double perovskites, Li 1.5 La 1.5 M O 6 ( M  = W 6+ , Te 6+ ), where an uncommon lithium-ion distribution enables macroscopic ion diffusion and tailored design of the composition allows us to switch functionality to either a negative electrode or a solid electrolyte. Introduction of tungsten allows reversible lithium-ion intercalation below 1 V, enabling application as an anode (initial specific capacity >200 mAh g -1 with remarkably low volume change of ∼0.2%). By contrast, substitution of tungsten with tellurium induces redox stability, directing the functionality of the perovskite towards a solid-state electrolyte with electrochemical stability up to 5 V and a low activation energy barrier (<0.2 eV) for microscopic lithium-ion diffusion. Characterisation across multiple length- and time-scales allows interrogation of the structure-property relationships in these materials and preliminary examination of a solid-state cell employing both compositions suggests lattice-matching avenues show promise for all-solid-state batteries. The development of the all solid-state battery requires the formation of stable solid/solid interfaces between different battery components. Here the authors tailor the composition to form both electrolyte and anode from the same novel family of perovskites with shared crystal chemistry.

Superconducting crystal balls Superconductivity and magnetic order are well known in C 60 compounds of the form A 3 C 60 (where A is an alkali metal). The spherical C 60 molecular ions in these superconducting crystals are almost exclusively arranged in a face-centred cubic lattice; the one exception is Cs 3 C 60 , where the known superconducting phase has a body-centred cubic packing. Now Ganin et al . have isolated the face-centred cubic polymorph of Cs 3 C 60 , and show that it too is superconducting, although its magnetic properties are very different from its body-centred cubic counterpart. The identification of these two distinct superconducting crystal structures in the same material should help to elucidate the nature of the subtle interplay between structure, magnetism and superconductivity in this and other high-temperature superconducting systems. Superconductivity and magnetic order are well known in C 60 compounds of the form A 3 C 60 (where A = alkali metal). The spherical C 60 molecular ions in these crystals are almost always arranged in a face-centred cubic (f.c.c.) packing, except in Cs 3 C 60 , where the known superconducting phase has a body-centred cubic (b.c.c) packing. Now the f.c.c. polymorph for Cs 3 C 60 has been isolated; it too is superconducting, although its magnetic properties are very different to those of its b.c.c counterpart. The crystal structure of a solid controls the interactions between the electronically active units and thus its electronic properties. In the high-temperature superconducting copper oxides, only one spatial arrangement of the electronically active Cu 2+ units—a two-dimensional square lattice—is available to study the competition between the cooperative electronic states of magnetic order and superconductivity 1 . Crystals of the spherical molecular C 60 3- anion support both superconductivity and magnetism but can consist of fundamentally distinct three-dimensional arrangements of the anions. Superconductivity in the A 3 C 60 (A = alkali metal) fullerides has been exclusively associated with face-centred cubic (f.c.c.) packing of C 60 3- (refs 2 , 3 ), but recently the most expanded (and thus having the highest superconducting transition temperature, T c ; ref. 4 ) composition Cs 3 C 60 has been isolated as a body-centred cubic (b.c.c.) packing, which supports both superconductivity and magnetic order 5 , 6 . Here we isolate the f.c.c. polymorph of Cs 3 C 60 to show how the spatial arrangement of the electronically active units controls the competing superconducting and magnetic electronic ground states. Unlike all the other f.c.c. A 3 C 60 fullerides, f.c.c. Cs 3 C 60 is not a superconductor but a magnetic insulator at ambient pressure, and becomes superconducting under pressure. The magnetic ordering occurs at an order of magnitude lower temperature in the geometrically frustrated f.c.c. polymorph (Néel temperature T N = 2.2 K) than in the b.c.c.-based packing ( T N = 46 K). The different lattice packings of C 60 3- change T c from 38 K in b.c.c. Cs 3 C 60 to 35 K in f.c.c. Cs 3 C 60 (the highest found in the f.c.c. A 3 C 60 family). The existence of two superconducting packings of the same electronically active unit reveals that T c scales universally in a structure-independent dome-like relationship with proximity to the Mott metal–insulator transition, which is governed by the role of electron correlations characteristic of high-temperature superconducting materials other than fullerides.

The Li + ion diffusion characteristics of V- and Nb-doped LiFePO 4 were examined with respect to undoped LiFePO 4 using muon spectroscopy (µSR) as a local probe. As little difference in diffusion coefficient between the pure and doped samples was observed, offering D Li values in the range 1.8–2.3 × 10 −10  cm 2 s −1 , this implied the improvement in electrochemical performance observed within doped LiFePO 4 was not a result of increased local Li + diffusion. This unexpected observation was made possible with the µSR technique, which can measure Li + self-diffusion within LiFePO 4 , and therefore negated the effect of the LiFePO 4 two-phase delithiation mechanism, which has previously prevented accurate Li + diffusion comparison between the doped and undoped materials. Therefore, the authors suggest that µSR is an excellent technique for analysing materials on a local scale to elucidate the effects of dopants on solid-state diffusion behaviour.

Herein, the direct synthesis of phase‐pure lithium aluminum titanium phosphate (Li1.3Al0.3Ti1.7(PO4)3, LATP) solid‐electrolyte powder in 220 min and relatively low temperatures (850 °C) is achieved via a new (cyclic) fast heat treatment (c‐FHT) route. The complex structural evolution highlights rate‐limited lithium incorporation of intermediate metal phosphates formed prior to the final phase‐pure LATP. The prepared LATP product powder displays similar bulk (2 × 10−10 cm2 s−1) and local (3 × 10−10 cm2 s−1) values for lithium diffusion coefficients (DLi) characterized by electrochemical impedance spectroscopy and muon spin relaxation (μSR), respectively. The similarity between both DLi values suggests excellent retention of inter‐ and intraparticle lithium diffusion, which is attributed to the absence of deleterious surface impurities such as AlPO4. A low‐energy barrier (Ea = 73 meV) of lithium diffusion is also estimated from the μSR data. Using a new cyclic fast heat treatment (c‐FHT) methodology, single‐phase lithium aluminium titanium phosphate (Li1.3Al0.3Ti1.7(PO4)3, LATP) powder has been synthesized in faster times and lower temperatures. Exceptional bulk (2 × 10−10 cm2 s−1) and local (3 × 10−10 cm2 s−1) diffusion coefficients are estimated by state‐of‐the‐art muon spin relaxation (μSR). Rate‐limiting processes during c‐FHT are identified using multiphase Rietveld refinement.

The development of the all solid-state battery requires the formation of stable solid/solid interfaces between different battery components. Here the authors tailor the composition to form both electrolyte and anode from the same novel family of perovskites with shared crystal chemistry.

The achiral organic radical dinitrophenyl nitronyl nitroxide crystallizes in two enantiomorphs, both being chiral tetragonal space groups that are mirror images of each other. Muon-spin rotation experiments have been performed to study the magnetic properties of these crystals and demonstrate that long-range magnetic order is established below a temperature of 1.10(1) K. Two oscillatory components are detected in the muon data, which show two different temperature dependences.

Although the coexistence of superconductivity and ferromagnetism in one compound is rare, some examples of such materials are known to exist. Methods to physically prepare hybrid structures with both competing phases are also known, which rely on the nanofabrication of alternating conducting layers. Chemical methods of building up hybrid materials with organic molecules (superconducting layers) and metal complexes (magnetic layers) have provided examples of superconductivity with some magnetic properties, but not fully ordered. Now, we report a chemical design strategy that uses the self assembly in solution of macromolecular nanosheet building blocks to engineer the coexistence of superconductivity and magnetism in [Ni 0.66 Al 0.33 (OH) 2 ][TaS 2 ] at ∼4 K. The method is further demonstrated in the isostructural [Ni 0.66 Fe 0.33 (OH) 2 ][TaS 2 ], in which the magnetic ordering is shifted from 4 K to 16 K. The co-existence of superconductivity and magnetism in single compounds is rare, and heterostructures containing both properties have only been made with complex techniques. Now, a molecular-building-block approach has been applied to match organic and inorganic layers to produce multifunctional materials.