Structure and Origin of New Stripe Domains in Oblique-Incidence Permalloy and Ni Films

Abstract

Stripe domains were observed in oblique-incidence 40-100% Ni-Fe films prepared at incident angles from 57° to 75° with thicknesses above 450A of either sign of uniaxial anisotropy. Lorentz microscopy at 100 kV reveals the structure of the domains as follows: 1. domain width is 1000-3500A and constant within a film, 2. in-plane component of magnetization is parallel to the incident direction, thus they are named “negative stripe domain”, 3. magnetization inclines at an angle below 60° from the film plane, and 4. both normal and in-plane components of magnetization change the direction in two neighboring domains. This structure can be considered analogous to that of an expanded cross-tie wall. At low frequency magnetization reversal, the negative stripe domains behave as a group and cause a two-stepped constricted hysteresis loop. The origin of these negative stripe domains is discussed in connection with the shape and pile of elongated columnar grains.