Low temperature magnetic and thermal properties of Co, Fe and Ni clusters

Abstract In this, thesis we study the theoretical and computational method to investigate properties of clusters and cluster-related phenomena specifically, magnetization, heat capacity and the influence number of atom on magnetization of Co, Fe & 𝑁𝑖 clusters. We have developed a theoretical framework for calculating magnetic heat capacity and reduced magnetization by combing the Heisenberg model and Bloch three-half power law. The temperature dependencies of spin-wave specific heat capacity and reduced magnetization are determined results shows T 3 2 ⁄ dependence of ferromagnetic case moreover the magnetization directly proportional with the number of atoms. As the temperature increases, the magnetization decreases on the other hand the values of magnetic heat capacity become increasingly higher than that of the values at low temperatures. The heat capacity vanishes at absolute zero and at low temperatures it is proportional to the absolute temperature. Magnetization M (T) curves are more shallow a small clusters (i.e. small number of atoms) than for large clusters and also critical temperature varies with cluster size. As the number of atom increases the magnetization increases accordingly. Determining the contribution of magnetic heat capacity is also important for many applications. We therefore, focus on understanding the ferromagnetic properties Co, Fe & 𝑁𝑖 transition metals clusters, within the frame work of the Heisenberg model, and the Bloch T 3 2 ⁄ law. The models taking into account, calculations are performed.