EFFECT OF BOUNDARY CONDITIONS ON MAGNETIZATION OF A NANO-SIZE FERROMAGNET

Based on a recently proposed analytic approach we explore the effect of boundary conditions on the magnetization of a finite size Heisenberg ferromagnet. Three types of boundary conditions are discussed on a specific example of the quantum spin S Heisenberg chain. This allows to demonstrate in an explicit form that discreteness of energy spectrum and sensitivity to boundary conditions become essential at the nanometric scale where a finite spin polarization can be achieved at reasonably high temperatures.