مرکز منطقه ای اطلاع رساني علوم و فناوري - Magnetic coupling between two Ni-Fe layers separated by SiO

Abstract :

The magnetic coupling between the magnetization in two nonmagnetostrictive Ni-Fe layers separated by a SiO layer has been investigated by means of a transverse susceptibility measurement. The main results are that 1) the coupling energy Ec per Unit area of the multilayered film has a form of $E_{c}= -A \\cos (\\phi_{1}-\\phi_{2})$ , where $\\phi_{1}-\\phi_{2}$ is the angle between the magnetization vectors in the two Ni-Fe layers, and 2) the dependence of the coupling constant on the thickness b of the intermediate SiO layer can be interpreted quantitatively by the combination of the coupling energy due to Néel\´s topography model and that due to the magnetostatic interaction between the magnetic free poles appearing at the edges of the two Ni-Fe layers. The former coupling energy is given by $E_{c1} = -frac{p}{2\\sqrt {2}}\\omega ^{2}M^{2} \\exp(-\\sqrt {2}pb) \\cos (\\phi_{1}-\\phi_{2})$ where $p=2\\pi/L$ and $L$ and $w$ are the wavelength and the amplitude of the undulation of the interface between Ni-Fe and SiO layers, respectively. The latter is given by $E_{c2} = frac{2M^{2}D^{2}}{R} \\ln (frac{R}{D+b}) \\cos (\\phi_{1}-\\phi_{2})$ where $D$ is the thickness of each Ni-Fe layer, and $R$ is the radius of the film.