Exploring the uncharacterized magnetic phases of ${\mathrm{Co}}^{2+}$ chain compounds is critical for finding new low-dimensional magnets hosting quantized excitations. We map the unexplored magnetic phases of the ${\mathrm{Co}}^{2+}$ chain compound ${\mathrm{Li}}_2{\mathrm{CoCl}}_4$. Magnetometry reveals magnetic ordering below 7 K with a metamagnetic transition near 16.5 kOe and a gradual transition to a field-aligned paramagnetic state above 31 kOe. Curie-Weiss fits to the high-temperature susceptibility reveal a high-spin (spin-$\frac{3}{2}$) state for cobalt. Heat capacity data, though, give a magnetic entropy change of 5.46 J/mol, consistent with cobalt effective spin-$\frac{1}{2}$ systems. To characterize the zero-field antiferromagnetic ordering, we separately calculated the energy of proposed magnetic structures with density functional theory and collected 3.5 K neutron diffraction data, finding that ${\mathrm{Li}}_2{\mathrm{CoCl}}_4$ has ferromagnetic chains with antiferromagnetic interactions between them. Increasing field rotates these spin chains, producing the antiferromagnetic to intermediate to paramagnetic transition sequence.

• Received 14 July 2023
• Accepted 22 September 2023

DOI:https://doi.org/10.1103/PhysRevMaterials.7.104405