The PSI Center for Neutron and Muon Sciences uses neutrons and muons to explore and understand matter and materials.
Lab News & Scientific Highlights
YBa1−𝑥Sr𝑥CuFeO5 layered perovskites: An attempt to explore the magnetic order beyond the paramagnetic-collinear-spiral triple point
Layered perovskites of general formula AA'CuFeO5 are characterized by the presence of spiral magnetic phases whose ordering temperatures 𝑇spiral can be tuned far beyond room temperature by introducing modest amounts of Cu/Fe chemical disorder in the crystal structure. This rare property makes these materials prominent candidates to host multiferroicity and magnetoelectric coupling at temperatures suitable for applications. Moreover, it has been proposed that the highest 𝑇spiral value that can be reached in this structural family ( ∼400 K) corresponds to a paramagnetic-collinear-spiral triple point with potential to show exotic physics. Since generating high amounts of Cu/Fe disorder is experimentally difficult, the phase diagram region beyond the triple point has been barely explored. To fill this gap we investigate here eleven YBa1−𝑥Sr𝑥CuFeO5 solid solutions (0≤𝑥≤1 ), where we replace Ba with Sr with the aim of enhancing the impact of the experimentally available Cu/Fe disorder. Using a combination of bulk magnetization measurements, synchrotron x-ray and neutron powder diffraction we show that the spiral state with 𝐤𝑠=(1/2,1/2,1/2±𝑞) is destabilized beyond a critical Sr content, being replaced by a fully antiferromagnetic state with ordering temperature 𝑇coll2≥𝑇spiral and propagation vector 𝐤𝑐2=(1/2,1/2,0). Interestingly, both 𝑇spiral and 𝑇coll2 increase with 𝑥 with comparable rates. This suggests a common, disorder-driven origin for both magnetic phases, consistent with theoretical predictions.
Connection between f-electron correlations and magnetic excitations in UTe2
The detailed anisotropic dispersion of the low-temperature, low-energy magnetic excitations of the candidate spin-triplet superconductor UTe2 is revealed using inelastic neutron scattering. The magnetic excitations emerge from the Brillouin zone boundary at the high symmetry Y and T points and disperse along the crystallographic b-axis. In applied magnetic fields ...
Small-angle scattering interferometry with neutron orbital angular momentum states
Methods to prepare and characterize neutron helical waves carrying orbital angular momentum (OAM) were recently demonstrated at small-angle neutron scattering (SANS) facilities. These methods enable access to the neutron orbital degree of freedom which provides new avenues of exploration in fundamental science experiments as well as in material characterization applications.
However, ....
Fractional quasiparticles in three dimensions
Specific signatures of fractionalization have been observed in a three-dimensional system known as quantum spin ice.
Evidence of antiferromagnetism in ultrathin metallic (111)-oriented LaNiO3 films
Antiferromagnets with exotic spin textures promise low-power spintronic devices with extremely high operating frequencies and resistance to external perturbations. In particular, the combination of highly tunable correlated electron physics, as in complex oxides, with metallicity and antiferromagnetism is desirable but exceedingly rare. LaNiO3, the lone example of a perovskite nickelate which is metallic across all temperatures, has long been a promising candidate, but the antiferromagnetic metallic state has remained elusive. We demonstrate the emergence ...
Origin of the Suppression of Magnetic Order in MnSi under Hydrostatic Pressure
We experimentally study the evolution of the magnetic moment 𝑚 and exchange interaction 𝐽 as a function of hydrostatic pressure in the zero-field helimagnetic phase of the strongly correlated electron system MnSi. The suppression of magnetic order at ≈1.5 GPa is shown to arise from the 𝐽 collapse and not from a quantum fluctuations induced reduction of 𝑚. Our work provides benchmarks ...
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Recent CNM publications
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Agarwal M, Zika A, Yücel M, Schweins R, Kohlbrecher J, Gröhn F
The role of light irradiation and dendrimer generation in directing electrostatic self-assembly
Polymers. 2025; 17(2): 170 (27 pp.). https://doi.org/10.3390/polym17020170
DORA PSI -
Ferretto I, Sharma A, Kim D, Della Ventura NM, Michler J, Capek J, et al.
Effect of precipitates on martensite formation and shape memory effect of FeMnSi-based shape memory alloys fabricated by laser powder bed fusion
Materials Science and Engineering A: Structural Materials: Properties, Microstructure and Processing. 2025; 921: 147592 (18 pp.). https://doi.org/10.1016/j.msea.2024.147592
DORA PSI -
Fu Y, Kohlbrecher J, Tichelaar FD, Hendrikx RWA, Böttger AJ, Brück E, et al.
Deformation-induced Au precipitation kinetics in Fe-Au-W alloys studied by time-resolved small angle neutron scattering
Materialia. 2025; 39: 102322 (11 pp.). https://doi.org/10.1016/j.mtla.2024.102322
DORA PSI