ON SOME PROBLEMS OF ISING MODEL IN THE QUANTUM THEORY OF MAGNETISM

This thesis consists of two parts; static and dynamic magnetic properties of random field Ising spin chains. The nearest-neighbour and next-nearest neighbour interactions are taken into consideration. Two distributions of random fields; a binary distributFor the static part, the metastable states, their magnetization, energy barriers and their distributions are exactly calculated for different number of spins and for different random fields. There is an exponential growth for the average number of energy In the dynamic part, Glauber model is used for chains of N coupled Ising spins in random fields to generate the equations of motion. We dealt with six-spin chains via computer simulations. The relaxation process is analyzed exactly. The number of diverginFinally, all the exact results obtained here for both the static and dynamic properties are compared with those of the earlier studied disordered magnetic systems. Our results are in complete agreements with many other Ising models in random field and spi