Honeycomb-lattice antiferromagnet Mn2V2O7: a temperaturedependent x-ray diffraction, neutron diffraction and ESR study

Temperature-dependent x-ray diffraction (XRD), neutron powder diffraction and high-field electron spin resonance (ESR) have been employed to study the structural and magnetic properties of distorted honeycomb lattice Mn2V2O7. The XRD data reveal that upon cooling Mn2V2O7 undergoes a martensitic-like beta-alpha structural phase transition at similar to 270 K. Upon heating, however, the reversible alpha-beta structural transition takes place at similar to 210 K, showing the first-order feature of the transition. The temperature range, where the two phases coexist, is well determined. With further decrease in temperature, a paramagnetic-to-antiferromagnetic (AFM) phase transition takes place at T-N = similar to 23 K as indicated by ESR and neutron powder diffraction data. The ESR data demonstrate the AFM resonance modes below T-N, which can be well understood by conventional AFM resonance theory with uniaxial anisotropy.