arXiv subjects

Siân Dutton

Publications and source records attributed to Siân Dutton.

3 recordsLinked to original sources

arXiv2025

Low-temperature magnetic behaviour on the triangular lattice in hexagonal Ba$_3$Tb(BO$_3$)$_3$

The hexagonal polymorph of Ba$_3$Tb(BO$_3$)$_3$ contains Tb$^{3+}$ ions on a quasi-2D triangular lattice, resulting in geometric magnetic frustration. Powder samples of Ba$_3$Tb(BO$_3$)$_3$ have been investigated using specific heat, powder neutron diffraction (PND), inelastic neutron scattering (INS) and muon-spin relaxation spectroscopy ($μ$SR). No long-range magnetic ordering is observed down to the lowest measured temperatures of 75 mK in PND and specific heat data and 1.5 K in the $μ$SR data. Modelling the INS spectrum using a point charge model suggests that the ground state is a singlet with a low-lying doublet on each of the two crystallographically independent Tb$^{3+}$ sites and that both the Tb ions display weak XY single-ion anisotropy.

cond-mat.str-el↗

arXiv2025

Magnetoelastic coupling in the stretched diamond lattice of TbTaO$_4$

The magnetic structure of diamond-like lattice has been studied extensively in terms of the magnetic frustration. Here we report the distortion of stretched diamond lattice of Tb$^{3+}$ (4$f^8$) in M-TbTaO$_4$ on application of a magnetic field. We have investigated the structural and magnetic properties of M phase terbium tantalate M-TbTaO$_4$ as a function of temperature and magnetic field using magnetometry and powder neutron diffraction. Sharp $λ$-shape transitions in $d(χT)/dT$, $dM/dH$ and specific heat data confirm the previously reported three-dimensional (3D) antiferromagnetic ordering at $T_N \approx 2.25$ K. On application of a magnetic field the Néel temperature is found to decrease and variable field neutron diffraction experiments below $T_N$ at 1.6 K show an increase in both the bond and angle distortion of the stretched diamond lattice with magnetic field, indicating a potential magneto-elastic coupling effect. By combining our magnetometry, heat capacity and neutron diffraction results we generate a magnetic phase diagram for M-TbTaO$_4$ as a function of temperature and field.

cond-mat.str-el↗

arXiv2020

Structure and magnetism of a new hexagonal polymorph of Ba$_3$Tb(BO$_3$)$_3$ with a quasi-2D triangular lattice

This article reports the structural and magnetic characterisation of a new hexagonal ($P6_3cm$) low-temperature phase of Ba$_3$Tb(BO$_3$)$_3$, isostructural with the heavier lanthanide borates with formula Ba$_3$Ln(BO$_3$)$_3$ (Ln = Dy-Lu). The crystal structure contains a quasi-two-dimensional (2D) triangular lattice of Tb$^{3+}$ ions and is predicted to display unusual magnetic behaviour as a result of the low dimensionality. Magnetic susceptibility $χ(T)$ shows antiferromagnetic interactions ($θ_{CW} = -7.15$ K) and no sharp ordering transition at $T \geq 2$ K, but analysis of $χ'(T)$, isothermal magnetisation and heat capacity suggests the possibility of short-range ordering at $T \approx 10$ K. The material exhibits an inverse magnetocaloric effect at $T < 4$ K.

cond-mat.str-el↗