High-field magnetization and electronic spin resonance study in the twisted honeycomb latticeα-Mn2V2O7.

We report the single-crystal growth of Mn2V2O7and the results of magnetic susceptibility, high-field magnetization up to 55 T and high-frequency electric spin resonance (ESR) measurements for its low-temperatureαphase. Two antiferromagnetic (AFM) ordering at 17.5 K and 3 K and obvious magnetic anisotropy are observed inα-Mn2V2O7upon cooling. In pulsed high magnetic fields, the compound reaches the saturation magnetic moment of ∼10.5µBfor each molecular formula at around 45 T after two undergoing AFM phase transitions atHc1≈ 16 T,Hc2≈ 34.5 T forH//[11-0] andHsf1= 2.5 T,Hsf2= 7 T forH//[001]. In these two directions, two and seven resonance modes are detected by ESR spectroscopy, respectively. Theω1andω2modes ofH//[11-0] can be well described by two-sublattice AFM resonance mode with two zero-field gaps at 94.51 GHz and 169.28 GHz, indicating a hard-axis feature. The seven modes forH//[001] are partially separated by the critical fields ofHsf1andHsf2, displaying the two signs of spin-flop transition. The fittings ofωc1andωc2modes yield zero-field gaps at 69.50 GHz and 84.73 GHz forH//[001], confirming the axis-type anisotropy. The saturated moment and gyromagnetic ratio indicate the Mn2+ion inα-Mn2V2O7is in a high spin state with orbital moment completely quenched. A quasi-one-dimensional magnetism with a zig-zag-chain spin configuration is suggested inα-Mn2V2O7, due to the special neighbor interactions caused by a distorted network structure with honeycomb layer.