Аннотация:The spin-1/2 Heisenberg honeycomb lattice has a particular position among quasi two-
dimensional materials. Due to low coordination number (z = 3) quantum
fluctuations are enhanced that causes a new interesting phenomena. Here we
present two examples of materials with honeycomb magnetic lattice of copper
ions with non-magnetic defects: InCu2/3V1/3O3 and Li3Cu2SbO6. Different kinds
of magnetic frustration create different magnetic ground states. Moreover, the
local resonance techniques like NMR and NQR gives us new information about
interplay of competing phenomena during a process of slowing down of spin
dynamics.