Magnetoelastic Coupling in U2Rh3Si5Studied by Thermal Expansion and Magnetostriction

Unusual magnetic ordering and metamagnetic transition in U 2 Rh 3 Si 5 were studied by thermal expansion and magnetostriction measurements. Thermal expansion along the three quasi-orthorhombic axes shows discontinuities with an anisotropic strain at the ordering temperature ( T o =25.5 K). The anisotropic strain increases with applied magnetic field but the volume change at T o becomes smaller opposite to the changes in the lattice length. Magnetostrictions also exhibit sharp and large length changes at the metamagnetic transition, showing the strong magnetostrictive coupling in U 2 Rh 3 Si 5 . The unusual behaviors of the magnetic and electronic properties at this transition could be due to the change in the electronic states arising from the large magnetostrictive effect.