Tunable bistability from magnetostriction (abstract)

Abstract

When a current passes along the axis of a [100] iron whisker in the presence of a field along the same axis, the magnetization in a central domain points along the field direction while the mangetization in four domains surrounding the central domain circulates about the axis, see Fig. 1. The size of the central domain grows with applied field, which overcomes the effect of the field from the current and the magnetostriction that favor the collapse of the central domain to an irreducible core. Depending on the current, the growth of the central domain can be a continuous or discontinuous process. At certain fields the energy is a double-well function of the size of the central domain, which determines the magnetization. The size of the energy barrier can be made arbitrarily small by suitable choice of the current. It is the ability to adjust the size of the barrier in such a clearly defined system that makes this an attractive experimental approach to understanding the role of fluctuations in magnetization processes. This structure has been verified using measurements of ac susceptibility.