Investigating Magnetoelastic Coupling in a Polar Helical Magnetic System: A Synchrotron X-Ray Diffraction Study

Our research focuses on Ni2ScSbO6, a layered triangular lattice material exhibiting complex correlated phenomena. At a temperature of TN=61 K, it develops noncollinear antiferromagnetic helical spin ordering. We observed a sharp, frequency-independent dielectric peak that is significantly reduced by an external magnetic field, indicating strong magnetodielectric coupling. Additionally, there is weak magnetoelectric coupling and notable phonon softening below this temperature, suggesting strong spin-phonon coupling. These intricate couplings are linked to the crystal structure, whereas phonon softening may also arise from magnetostriction effects. Understanding the structural evolution in Ni2ScSbO6 around TN is very crucial to elucidate the aforementioned intriguing phenomena, which can be probed through temperature-dependent high-resolution synchrotron X-ray diffraction studies.