We have investigated the magnetic properties of CuNCN, the first nitrogen-based analog of cupric oxide CuO. Our muon-spin relaxation, nuclear magnetic resonance, and electron-spin resonance studies reveal that classical magnetic ordering is absent down to the lowest temperatures. However, a large enhancement of spin correlations and an unexpected inhomogeneous magnetism have been observed below 80 K. We attribute this to a peculiar fragility of the electronic state against weak perturbations due to geometrical frustration, which selects between competing spin-liquid and more conventional frozen states.
COBISS.SI-ID: 24909863
We presented an electron spin resonance (ESR) investigation of the acentric Ba3NbFe3Si2O14, featuring a unique single-domain double-chiral magnetic ground state. Combining simulations of the ESR linewidth anisotropy and the antiferromagnetic-resonance modes allows us to single out the Dzyaloshinsky-Moriya (DM) interaction as the leading magnetic anisotropy term. We demonstrate that the rather minute out-of-plane DM component dc=45 mK is responsible for selecting a unique ground state, which endures thermal fluctuations up to astonishingly high temperatures.
COBISS.SI-ID: 25416231
We present an electron spin resonance (ESR) study of a single-crystalline spin chain system CuSe2O5 in the frequency range between 9 and 430 GHz. In a wide temperature range above the Neel temperature TN = 17 K we observe a strong and anisotropic frequency dependence of a resonance linewidth. Although a sizable interchain interaction JIC ≈ 0.1J (J is the intrachain interaction) is present in this system, the ESR results agree well with the Oshikawa-Affleck theory for a one-dimensional S = 1/2 Heisenberg antiferromagnet. This theory is used to extract the anisotropies present in CuSe2O5.We find that the symmetric anisotropic exchange Jc = (0.04 ± 0.01)J and the antisymmetric Dzyaloshinskii-Moriya (DM) interaction D = (0.05 ± 0.01)J are very similar in size in this system. Staggered field susceptibility induced by the presence of the DM interaction is witnessed in the macroscopic susceptibility anisotropy.
COBISS.SI-ID: 25329447