Through neutron powder diffraction, we confirm the double perovskite Nd₂NiMnO₆ adopts a monoclinic P2₁/n structure with nearly complete B-site ordering of Ni²⁺ and Mn⁴⁺. Below T₁ = 198 K, magnetic susceptibility and neutron data reveal the Ni²⁺ and Mn⁴⁺ sublattices undergo ferromagnetic ordering, driven by strong 3d-3d exchange interactions. Upon cooling through T₂ = 22 K, a secondary...
Special care is needed for spin echo spectroscopy of spin excitations. Even in the case of antiferromagnets (AF), which do not depolarize the neutron beam, the scattering on spin excitations induces neutron spin flips that affect the spin echo signal. We review three cases from TRISP at the FRM II. The first case is a straightforward example of magnons in the uniaxial AF MnF2, where by proper...
We have Performed an inelastic neutron scattering (INS) investigation on the trimer ruthenate Ba$_5$Ru$_3$O$_{12}$, that undergoes long-range antiferromagnetic ordering at $T_\mathrm{N}$ = 60 K. The INS spectra suggest two distinct spin-wave excitations one at 5.6 meV, which is less intence and a broader intense excitation around 10-15 meV. Notably, these magnetic excitations persist well...
Rare-earth trihalides are attracting attention in the field of quantum matter for their potential to exhibit exotic ground states arising from interactions among magnetic moments, including competing interactions or geometrical frustration. While the late rare-earth halides adopt a honeycomb structure, the early rare-earth trihalides adopt a 3D UCl3-type structure, with ABAB stacked triangular...
The study of critical phenomena has always been deeply connected with magnetism in solid state materials. Nickel, one of the three archetypical room temperature ferromagnets, is understood to be an itinerant system with a high degree of localization regarding its magnetically active electron states. We report a high-resolution neutron spectroscopy investigation of nickel (Ni) near its Curie...
The natural mineral clinoatacamite, [Cu2Cl(OH)3], exhibits low-temperature, frustrated magnetic behaviour where competing interactions are responsible for novel magnetic properties. Attempts to establish the magnetic phases in this material have been undertaken and an unconventional applied field (H||b) phase diagram has been revealed [1]. Two critical transition temperatures at zero field...
