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Abstract: We present the results of a resonant x-ray-diffraction experiment, resolving both charge and spin textures in the intermetallic topological magnet Eu⁢(Al1−𝑥⁢Ga𝑥)4 (𝑥 = 0.1). Below ≈75 K the system develops a charge-density wave (CDW) with propagation vector 𝐤CDW≈(0,0,0.18). The CDW order parameter grows monotonically on cooling until ≈15 K, when a sudden decrease in the CDW amplitude occurs. Pairs of magnetic satellites of the (0, 0, 8) Bragg reflection corresponding to two distinct domains, 𝐤1 = (±𝛿m, 0, 0), 𝐤2 = (0, ±𝛿m, 0), 𝛿m=0.2002⁢(4) were studied at the Eu 𝐿3 edge, appearing below 𝑇N = 14.8 K. Our measurement of 𝑇N is exactly coincident with the sudden drop in the CDW amplitude, which suggests strong coupling between the charge and spin orders, as observed in other compounds of the Eu⁢(Al1−𝑥⁢Ga𝑥)4 series. Azimuthal measurements were consistent with a single helical spin arrangement having an elliptical envelope of 𝜇Y/𝜇Z = 1.19(6) for the 𝐤2 domain, and a tilted helical (helicoidal) spin arrangement for the 𝐤1 domain, with 𝜇Y/𝜇Z = 1.14(4) and 𝜇X/𝜇Z = 0.20(2) that may be hidden for the 𝐤2 domain due to multiple subdomains. Temperature evolution of the magnetic satellite intensities in linear and circularly polarized light found the respective ratio to be invariant with temperature, suggesting a single helicoidal magnetic phase throughout the measured temperature range. This behavior is unlike the 𝑥 = 0 material, in which a spin-density wave forms first, transitioning to a helical ground state on cooling through intermediate phases. Future theoretical work on the Eu electronic ground state, supported by related experiments, will help understand the effects of Ga substitution on the evolution of the magnetic structure.

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Abstract: We characterize the magnetic ground state of the newly synthesized lanthanide intermetallic GdNiSn4via resonant elastic x-ray scattering measurements. This compound forms distorted square nets of Gd that initially order magnetically below 23 K, followed by a lower-temperature transition at 16 K. Our scattering data identify the ground state order as a single-q incommensurate, collinear order that slides towards a commensurate wave vector above the 16 K transition. Magnetic symmetry analysis combined with azimuthal dependence resolves the ground state magnetic structure as a moment-modulated spin density wave state with Gd moments oriented parallel to the in-plane 𝑎-axis. We discuss connections between the observed magnetic order and electronic properties in this square-net compound.

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Abstract: We present a combined x-ray and polarized neutron scattering study on chiral, polar and magnetoeletric NiCo2⁢TeO6 single crystals with different net crystal chiralities as characterized by optical methods. The rastering images taken with a micrometer-sized polarized x-ray beam unambiguously reveal the coupling of crystal and magnetic chiralities in a heterochiral sample. Spherical neutron polarimetry experiments on a different, structurally enantiopure sample—as evidenced by polarized x-ray scattering—reveal a homochiral magnetic spiral, which proves the stabilization of a single helical handedness despite the intertwined structural helices in the ferri-chiral crystal structure.

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Abstract: We present results of an experimental study on single crystals of a 5d double perovskite Ba2CaReO6. Magnetization measurements reveal a weak splitting between zero-field-cooled and field-cooled protocols below 12 K. At magnetic fields above 1 T the splitting is absent and the magnetic susceptibility is featureless. A detailed specific heat study in a wide temperature range and comprising different heat pulses did not reveal any indication of a thermodynamic phase transition. At low temperatures we do observe specific heat deviating from a phonon background, leading to a total electronic entropy release of . Resonant and non-resonant x-ray diffraction of characteristic Bragg peaks indicates a significant presence of disorder, potentially related to random tilts and rotations of rigid ReO6 octahedra.

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Abstract: Four novel carbazole-based photopolymerizable liquid crystals (PLCs) incorporating diacrylates or nonconjugated dienes were designed and synthesized to study their mesomorphic behavior and photocuring properties, with a focus on future applications in 4D printing. A combined analysis protocol using polarized optical microscopy (POM), differential scanning calorimetry (DSC), small-angle X-ray scattering (SAXS), and wide-angle X-ray scattering (WAXS) revealed a favorably wide range of nematic phases near room temperature and a slow tendency to crystallize. This should be advantageous in applications requiring good surface-alignment of the reactive mesogen in the nematic phase. This behavior could be attributed to the effects of polymerization under prolonged high temperatures for acrylates and the high entropy of long, branched, flexible alkyl chains in dienes. The polymerization process induces a kinetic competition between LC ordering and network formation. This work establishes protocols for real-time phase monitoring during polymerization, resolving longstanding ambiguities in LC phase identification under thermal polymerization. Furthermore, photocuring tests of the acrylate and diene monomers demonstrated high photopolymerization efficiency and good thermal stability, particularly for the acrylate monomers.