Anisotropic ${\mathrm{Ru}}^{3+} 4{d}^{5}$ magnetism in the $\ensuremath{\alpha}\ensuremath{-}{\mathrm{RuCl}}_{3}$ honeycomb system: Susceptibility, specific heat, and zero-field NMR

Rapid Communication

Anisotropic ${Ru}^{3 +} 4 d^{5}$ magnetism in the $α - {RuCl}_{3}$ honeycomb system: Susceptibility, specific heat, and zero-field NMR

M. Majumder, M. Schmidt, H. Rosner, A. A. Tsirlin, H. Yasuoka, and M. Baenitz

Phys. Rev. B 91, 180401(R) – Published 7 May 2015

Abstract

Hexagonal $α$ -Ru trichloride single crystals exhibit a strong magnetic anisotropy and we show that upon applying fields up to 14 T in the honeycomb plane the successive magnetic order at $T_{1} = 14 K$ and $T_{2} = 8 K$ could be completely suppressed, whereas in the perpendicular direction the magnetic order is robust. Furthermore, the field dependence of $χ (T)$ implies coexisting ferro- and antiferromagnetic exchange between in-plane components of ${Ru}^{3 +}$ spins, whereas for out-of-plane components a strong antiferromagnetic exchange becomes evident. ${}^{101}{Ru}$ zero-field nuclear magnetic resonance in the ordered state evidence a complex (probably noncoplanar chiral) long-range magnetic structure. The large orbital moment on ${Ru}^{3 +}$ is found in density-functional calculations.