Structural and magnetic properties of the quantum magnet BaCuTe2O6

Abstract

We investigate the structural and magnetic properties of the quantum magnet BaCuTe 2 O 6 . This compound is synthesized in powder and single crystal form for the first time. Synchrotron x-ray and neutron diffraction reveal a cubic crystal structure (P4 1 32) where the magnetic Cu 2+ ions form a complex network. Heat capacity and static magnetic susceptibility measurements suggest the presence of antiferromagnetic interactions with a Curie-Weiss temperature of ≈− 33 K, while long-range magnetic order occurs at the much lower temperature of ≈6.3 K. The magnetic structure, solved using neutron diffraction, reveals antiferromagnetic order along chains parallel to the a, b, and c crystal axes. This is consistent with the magnetic excitations which resemble the multispinon continuum typical of the spin-1/2 Heisenberg antiferromagnetic chain. A consistent intrachain interaction value of ≈34 K is achieved from the various techniques. Finally the magnetic structure provides evidence that the chains are coupled together in a noncollinear arrangement by a much weaker antiferromagnetic, frustrated hyperkagome interaction.

Magnetic excitation spectrum and Hamiltonian of the quantum spin chain compound BaCuTe2O6

“…This was confirmed by inelastic neutron scattering measurements, which observed the characteristic spinon continuum expected for a spin-1/2 Heisenberg antiferromagnetic chain, allowing comparison to theory, which yielded J 3 = 2.90 meV [10]. Long-range antiferromagnetic order occurs at the much lower temperature of T N = 6.1 − 6.3 K [10,19] revealing the presence of weak interchain interactions. The magnetic structure was found to follow the 2 × 1 2 irreducible representation [10].…”

“…As for SrCuTe 2 O 6 , the unfrustrated J 3 interaction is also dominant and antiferromagnetic in BaCuTe 2 O 6 , giving rise to spin chains parallel to the a, b, and c axes. The intrachain interaction was found to have strength J 3 = 2.93 − 3.19 meV from DC susceptibility and heat capacity measurements [10,19]. This was confirmed by inelastic neutron scattering measurements, which observed the characteristic spinon continuum expected for a spin-1/2 Heisenberg antiferromagnetic chain, allowing comparison to theory, which yielded J 3 = 2.90 meV [10].…”

“…Long-range antiferromagnetic order occurs at the much lower temperature of T N = 6.1 − 6.3 K [10,19] revealing the presence of weak interchain interactions. The magnetic structure was found to follow the 2 × 1 2 irreducible representation [10]. It is illustrated by the red arrows along with the exchange interactions J 1 , J 2 , J 3 , and J 6 in Fig.…”

“…The behavior of SrCuTe 2 O 6 is very different from PbCuTe 2 O 6 . In this compound the unfrustrated J 3 interaction [10]. (a) Includes the first J 1 (grey line) and third J 3 (green line) nearest-neighbor interactions.…”

“…The intrachain interaction was found to have strength J 3 = 2.93 − 3.19 meV from DC susceptibility and heat capacity measurements [10,19]. This was confirmed by inelastic neutron scattering measurements, which observed the characteristic spinon continuum expected for a spin-1/2 Heisenberg antiferromagnetic chain, allowing comparison to theory, which yielded J 3 = 2.90 meV [10]. Long-range antiferromagnetic order occurs at the much lower temperature of T N = 6.1 − 6.3 K [10,19] revealing the presence of weak interchain interactions.…”