Frustration and dimerization in ferrimagnetic systems

We have studied the spin-Peierls transition of an alternating spin Heisenberg system on a chain and a square lattice using linear spin wave theory for three kind of alternating spin systems. Different possibilities of dimerization in the case of a square lattice were included. We found that LSWT is good enough to predict the qualitative behavior of ferrimagnetic systems. The ground state energy as well as sublattice magnetization decrease continuously with increasing dimerization in one and two dimensions for both the methods used. In 2D, we have proposed an exchange coupling based on the ansatz $J(a)=frac{J}{a}$ to be able to distinguish between the different dimerized configurations. SPT in ferrimagnets was found to be conditional for chains as well as square lattices and the long range order of the system was destroyed due to dimerization. Ferrimagnets, whether in one or two dimensions, have short correlation lengths.

Autorentext

I looked into the properties of ferrimagnetic Heisenberg model within linear as well as nonlinear spin wave formalisms in the presence of both dimerization and frustration, focusing on the competing effects of the two. The effect of temperature dependent of these interactions was also investigated.