Exactly solvable Ising--Heisenberg chain with triangular XXZ-Heisenberg   plaquettes
  A mixed Ising-Heisenberg spin system consisting of triangular XXZ-Heisenberg spin clusters assembled into a chain by alternating with Ising spins interacting to all three spins in the triangle is considered. The exact solution of the model is given in terms of the generalized decoration--iteration map and within the transfer-matrix technique. Exact expressions for thermodynamic functions are derived. Ground state phase diagrams, thermodynamic and magnetic properties of the system are examined. 
Diana Antonosyan, Stefano Bellucci and Vadim Ohanyan