Approach to control magnetic plateau in tetrameric magnetic systems

We study the magnetic behavior of a tetrameric magnetic system with four antiferromagnetic couplings(J₁-J₂-J₃-J₄), where J₄ is the inter-cell coupling and J₁,J₂,J₃ are the intra-cell couplings, by using Green's function theory. The Magnetic-field curves shows that there are three plateaus (M = 0, 1 and saturated magnetization) and two gapless phases distinguished by four critical lines, and the plateaus widen or narrow with the inter-cell coupling(J₄), which are further explained using the energy spectrum. In addition, it is found that the magnetic contribution from each site of the unit cell is different due to the competition of the nearest neighboring pair interactions, which is demonstrated by the concurrence of the biparticle quantum state.