Bonding mechanism and magnetic ordering in Laves phase λ1−MgCo2 intermetallic compound from theoretical and experimental studies

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New type of magnetic structure in the R2T2X group Tb2Pd2In

Anisotropy of bulk magnetic properties and magnetic structure studies of a Tb2Pd2In single crystal by means of bulk magnetization methods and neutron diffraction techniques confirmed the antiferromagnetic order below the N el temperature 29.5 K. The collinear magnetic structure of Tb magnetic moments aligned along the tetragonal c axis is characterized by a propagation vector k 1 4, 1 4, 1 2 , yielding an equal moment structure with alternating coupling between nearest as well as next nearest Tb neighbors within the basal plane and antiferromagnetic coupling between the c axis neighbors. In the context of magnetism of R2T2X compounds, where R stands for rare earth or actinide element, such collinear structure with long wavelength periodicity represents a new type of magnetic structure

Heavy-Fermion Properties of Yb2Pd2SnH≈2

A hydride of Yb2Pd2Sn could be synthesized with approximately 2 H atoms per f.u. The hydrogenation leads to a volume expansion while preserving the tetragonal symmetry (P4/mbm). The lattice reaction is strongly anisotropic, and the 5% expansion in c is partly compensated by the 0.5% compression in a. The hydride is paramagnetic at least down to 0.5 K. Yb remains at or very close to the 3+ (4f 13) state, as in Yb2Pd2Sn. Specific heat C/T vs. T shows an upturn existing already in Yb2Pd2Sn, but it is much more pronounced in the hydride (1.8 J/mol f.u. K2 for T ! 0, i.e., more than twice higher than in its precursor). This is interpreted as lowering the Kondo temperature due to H bonding

Insight into the physics of the 5f -band antiferromagnet U₂Ni₂Sn from the pressure dependence of crystal structure and electrical resistivity

A resistivity study of a single crystal of U2Ni2Sn has been performed at ambient pressure and under hydrostatic pressure up to p=3.3GPa. It revealed Fermi-liquid behavior accompanied by spin excitations with an energy gap Δ=30-55K in the whole pressure range. The Néel temperature varies with pressure in a nonmonotonous way. It increases at the rate dTN/dp=+0.6K/GPa, and later, after passing through the maximum at ≈3 GPa, it starts to decrease quickly. High-pressure x-ray diffraction indicated that an orthorhombic distortion of the tetragonal structure takes place around the pressure of this TN maximum. The computational study based on the density functional theory illustrates that the loss of magnetism in U2Ni2Sn with pressure is primarily due to 5f-band broadening, which results from the collapse of the U spacing within the U-U dimers. © 2021 American Physical Society