ABSTRACT
In this chapter, the author shows the main properties of a helimagnetic thin film with quantum Heisenberg spin model by using the Green’s function (GF) method. Surface spin configuration is calculated by minimizing the spin interaction energy. It is shown that the angles between the spins near the surface are strongly modified with respect to the bulk configuration. In spite of their long history, the nature of the phase transition in the bulk helimagnets as well as in other noncollinear magnets such as stacked triangular XY and Heisenberg antiferromagnets has been elucidated only recently. Helical magnets present the potential applications in the spintronics with predictions of spin-dependent electron transport in these magnetic materials. In the chapter, the classical bulk ground-state spin configuration in a thin film is exactly calculated and is found to be strongly modified near the film surface.
