title: Magnetization and spin gap in two-dimensional organic ferrimagnet BIPNNBNO.
abstract: A magnetization process in the two-dimensional ferrimagnet BIPNNBNO is analyzed. The compound consists of ferrimagnetic (1,1/2) chains coupled by two sorts of antiferromagnetic interaction. Whereas the behavior of the magnetization curve in higher magnetic fields can be understood within a process for the separate ferrimagnetic chain, the appearance of the singlet plateau at lower fields is an example of non-Lieb-Mattis type ferrimagnetism. By using the exact diagonalization technique for finite clusters of size 4 × 6, 4 × 8 and 4 × 10 we show that the interchain frustration coupling plays an essential role in stabilization of the singlet phase. These results are complemented by an analysis of four cylindrically coupled ferrimagnetic (1,1/2) chains via an Abelian bosonization technique and an effective theory based on the XXZ spin-1/2 Heisenberg model when the interchain interactions are sufficiently weak/strong, respectively.
authors: Institute of Natural Sciences, Ural Federal University, Ekaterinburg, Russia.
authors: A S
authors: AS
authors: Ovchinnikov
authors: V E
authors: VE
authors: Sinitsyn
authors: I G
authors: IG
authors: Bostrem
authors: Y
authors: Y
authors: Hosokoshi
authors: K
authors: K
authors: Inoue