Magnetic structure and low-temperature properties of geometrically frustrated SrNd2O4

Magnetic short-range order in polycrystalline SrGd2O4 and SrNd2O4 studied by reverse Monte Carlo simulations

“…Note that there exists an experimental uncertainty of a few tenths of degrees in the thermometry, as well as the possibility of a comparably small temperature gradient across the height of the sample, such that the 2.2 K data from D4 on the Nd compound could possibly straddle T N . By comparison with the published diffraction patterns and magnetic structures, 10, 13 we can attribute the strongest scattered intensities to the magnetic (120) and (1 1 2 1 2 ) reflections for the Gd and the Nd compound, respectively. The program Spincorrel included in the Spinvert package can be used to obtain a better understanding from a disordered system in terms of local spin correlations in real space by reducing the spin configuration in the large simulation box to the expectation value of dot products between spin-spin pairs as a function of distance, which is given by the spin-correlation function (SCF) ⟨S(0) • S(r)⟩.…”

“…The spin dimensionality for SrNd 2 O 4 was chosen to be easy-plane within the ab-plane following the results concerning the canted magnetic structure. 13 In agreement with the subtraction of a 50 K paramagnetic diffraction pattern from the experimental data sets, thus retaining only magnetic scattering from spin correlations, the corresponding magnetic scattering intensities, normalized to barns/str/Ln-atom as a differential scattering cross-section, are calculated by Spinvert according to:…”

“…11,12 The magnetic properties and the magnetic structure have recently been investigated based on powder samples. 13 While the Gd compound reveals a k = 0 magnetic structure with parallel nearest-neighbor spins being longitudinally ordered with respect to the one-dimensional chains along the c axis, the Nd compound has a 4 times larger magnetic unit cell described by the propagation vector k = (0 1 2 1 2 ) and a transversal spin order with antiparallel nearestneighbor alignment along the 1D chains.…”

“…18 Owing to the strong geometrical frustration both SrGd 2 O 4 and SrNd 2 O 4 display significant magnetic diffuse scattering well above the Néel temperature, but also within their magnetically ordered phases, since one of the two magnetic sites has a substantially reduced ordered moment as determined by Rietveld refinement. 10, 13 We have studied the temperature dependence of the short-range spin correlations by means of total-scattering powder neutron diffraction combined with reverse Monte Carlo (RMC) simulations and magnetic pair-distribution function (mPDF) analysis, which reveal also the dynamic short-ranged spin correlations well above T N and thus shed light on how the static long-range order below T N is established in these systems as T decreases.…”

Panther — the new thermal neutron time-of-flight spectrometer at the ILL

“…Panther entered the user program of the ILL in 2020, and the average oversubscription factor since then is in the range 3-4. The first official user experiment on a powder sample concerned a crystal-field study of a geometrically frustrated magnet [7] and the first single-crystal experiment was a study of Dirac magnons in a honeycomb ferromagnet [8]. An example of a constant-energy slice from the latter experiment is shown in Fig.…”