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Despite decades of theoretical work devoted to the study of frustrated spin ladders (see, e.g., [1] and references therein), real material realizations of such systems still remain limited. In this work, we investigate the magnetic properties of the new compound Li₂O(CuSO₄)₂ [2], which appears as a rare realization of a frustrated two-leg spin ladder in its high-temperature tetragonal structure [3]. Through a combined experimental and theoretical approach, we demonstrate that most of the magnetic frustration is removed by a structural transition, occurring at about 135K, and leading to a strong magnetic dimerization of the Cu ions [4]. Furthermore, we present recent results obtained from infrared spectroscopy and inelastic neutron scattering, providing first information on the magnetic excitations in this system.

[1] T. Vekua and A. Honecker, Phys. Rev. B 73, 214427 (2006).
[2] M. Sun, et al., Chem. Mat. 27, 3077 (2015).
[3] G. Rousse, et al., Phys Rev B 95, 144103 (2017).
[4] O. Vaccarelli, et al., Submitted.