Insight into the physics of the 5f-band antiferromagnet U2Ni2Sn from the pressure dependence of crystal structure and electrical resistivity
Abstrakt
A resistivity study of a single crystal of U2Ni2Sn has been performed at ambient pressure and under hydrostatic pressure up to p = 3.3 GPa. It revealed Fermi-liquid behavior accompanied by spin excitations with an energy gap Delta = 30-55K in the whole pressure range.
The Neel temperature varies with pressure in a nonmonotonous way. It increases at the rate dT(N)/dp= +0.6 K/GPa, and later, after passing through the maximum at approximate to 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 T-N 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.