The phase diagram of the Heisenberg ferromagnetic model in the presence of a magnetic random field (we have used bimodal distribution) of spin S=1/2 (quantum case) and S=∞ (classical case) on a simple cubic lattice is studied within the framework of the effective-field theory in finite cluster...

A molecular-based magnetic material AFeIIFeIII(C2O4)3 (A = organic cation) with a honeycomb structure is studied. The molecular-based magnet system consists of mixed spin-2 and spin- 5/2 honeycomb lattices with ferrimagnetic interlayer coupling. The magnetization, hysteresis loops and initial...

In this work, a study on a site diluted Ising model system is applied to the magnetic properties of the bcc disordered phase of FeAl alloys by employing effective field theory. Here, one suggests a new approach to exchange interaction between nearest neighbors of Fe that depends on the powers of...

Analytical solutions for the time-dependent autocorrelation function of the classical and quantum mechanical spin dimer with arbitrary spin are presented and compared. For large spin quantum numbers or high temperature the classical and the quantum dimer become more and more similar, yet with...

The transition behaviour of a magnetic system consisting of numerous nano-sized clusters with a zero external field was studied. We investigated the transition from superparamagnetism (SP) to ferromagnetic single-domain (SD) state due to the increase of cluster size by Monte Carlo simulation of...

We have extended the application of quantum renormalisation group (QRG) to the anisotropic Heisenberg model with next-nearest neighbour (n-n-n) interaction. The second order correction has to be taken into account to get a self similar renormalised Hamiltonian in the presence of...

Boundary contributions of the magnetizations of several isotropic magnets, which are generalized antiferromagnetic Heisenberg models in open chains, are evaluated. The boundary magnetization approaches zero logarithmically as the external field goes to zero, in each of the models, namely the...

In this paper we study the spin wave transmission spectra of quasiperiodic magnetic multilayers following Fibonacci, double period and Thue–Morse sequences. We consider multilayers that are composed of two simple cubic ferromagnetic materials surrounded by two semi-infinite slabs of a third...

We study kink states of quantum, ferromagnetic, easy axis spin 12 chains at zero temperature. These are produced by applying opposite magnetic fields on the two end sites of the chain. For sufficiently strong anisotropy and boundary field, we obtain estimates on the wave function of the lowest...

A semi-classical theory is employed to investigate the spin wave spectra and the localization profile of linear quasiperiodic binary superlattices, where one of their components is a ferromagnetic material, the other one being an antiferromagnet. The calculations are carried out for the...