Ising-type quasi-one-dimensional ferromagnetism with anisotropic hybridization inUNi4P2

Abstract

We report single-crystal growth and demonstrate Ising-type ferromagnetism with a Curie temperature of 25 K in ${\mathrm{UNi}}_{4}{\mathrm{P}}_{2}$ by means of magnetization, electrical transport, and specific heat measurements. Uniaxial anisotropy in magnetism and $cf$ hybridization are well reflected not only in the crystallographic $ac$ plane but also within the basal plane of the tetragonal unit cell owing to the quasi-one-dimensional crystal and electronic structure of ${\mathrm{UNi}}_{4}{\mathrm{P}}_{2}$. The strong anisotropy between the $c$ axis and the tetragonal basal plane is retained up to 57 T, while the intraplane anisotropy in the basal plane gradually vanishes at higher fields. Our results show that anisotropic electron correlations may stabilize the elusive Ising-type ferromagnetic order in one dimension at nonzero temperatures, presumably with its own characteristic universality class.