Magnetic anisotropy of spin tetramer system SeCuO${}_3$ studied by torque magnetometry and ESR spectroscopy

Abstract

We present an experimental study of macroscopic and microscopic magnetic anisotropy of a spin tetramer system SeCuO${}_3$ using torque magnetometry and ESR spectroscopy. Large rotation of macroscopic magnetic axes with temperature observed from torque magnetometry agrees reasonably well with the rotation of the $\text{g}$ tensor above $T\gtrsim 50$~K. Below 50~K, the $\text{g}$ tensor is temperature independent, while macroscopic magnetic axes continue to rotate. Additionally, the susceptibility anisotropy has a temperature dependence which cannot be reconciled with the isotropic Heisenberg model of interactions between spins. ESR linewidth analysis shows that anisotropic exchange interaction must be present in SeCuO${}_3$. These findings strongly support the presence of anisotropic exchange interactions in the Hamiltonian of the studied system. Below $T_N=8$~K, the system enters a long - range antiferromagnetically ordered state with easy axis along the $<\bar{1}01{>}^{\ast }$ direction. Small but significant rotation of magnetic axes is also observed in the antiferromagnetically ordered state suggesting strong spin-lattice coupling in this system.

14 pages, 13 figures

References in corpus (3)

• Magnetic Susceptibility of the Kagome Antiferromagnet ZnCu3(OH)6Cl2
• Structural and magnetic dimers in the spin-gapped system CuTe2O5
• Uniform and staggered magnetizations induced by Dzyaloshinskii-Moriya interactions in isolated and coupled spin 1/2 dimers in a magnetic field