Magnetoelastic couplings in the deformed Kagomé quantum spin lattice of volborthite

Abstract

Microscopic spin interactions on a deformed Kagomé lattice of volborthite are investigated through magnetoelastic couplings. A negative longitudinal magnetostriction $\Delta L<0$ in the $b$ axis is observed, which depends on the magnetization $M$ with a peculiar relation of $\Delta L/L\propto M^{1.3}$. Based on the exchange striction model, it is argued that the negative magnetostriction originates from a pantograph-like lattice change of the Cu-O-Cu chain in the $b$ axis, and that the peculiar dependence arises from the local spin correlation. This idea is supported by DFT+$U$ calculations simulating the lattice change and a finite-size calculation of the spin correlation, indicating that the recently proposed coupled-trimer model is a plausible one.

References in corpus (4)

• Vector chiral and multipolar orders in the spin-1/2 frustrated ferromagnetic chain in magnetic field
• One-Third Magnetization Plateau with a Preceding Novel Phase in Volborthite
• A novel crystal polymorph of volborthite, Cu3V2O7(OH)2 2H2O
• 100 MHz high-speed strain monitor using fiber Bragg grating and optical filter applied for magnetostriction measurements of cobaltite at magnetic fields beyond 100 T