Magnetization changes visualized using photoemission electron microscopy

Photoemission electron microscopy was used to visualize the motion of magnetic domains on a sub-nanosecond timescale. The technique exploits the imaging of magnetic domains using soft X-ray circular dichroism, with the special feature that the instrument utilizes a fast image acquisition system with intrinsic 125 ps time resolution. The overall time resolution used is about 500 ps. Different domains and domain movements have been observed in lithographically-produced Permalloy structures on a copper microstrip-line. A current pulse of I = 0.5 A with rise times of about 300 ps switched the Permalloy islands from a Landau-Lifshitz type domain configuration into metastable s-state domain configurations. A pulse with opposite direction could reverse these s-type patterns. Photoemission electron microscopy was employed to observe the domain movements while repeating current pulses passed the microstrip-line. Using small unipolar amplitudes, only the cross-tie walls of the s-type patterns disappear and the pattern becomes "fuzzy", e.g. the domain rims are not sharp and some domains change their size. Before the structure switches at a current threshold, it is more fluctuating as shown by significant differences in sharpness of the islands rim and the inter-domain boundaries show. The device behavior complicates when a bi-polar pulse is applied. Switching and oscillating of domains is observed in various manners, e.g. very tiny domains appear and unify again. (C) 2004 Elsevier B.V. All rights reserved

Buyer Search Costs and Endogenous Product Design

Buyer search costs for price are changing in many markets. Through a model of buyer and seller behavior, I consider the effects of changing search costs on prices both when product differentiation is fixed and when it is endogenously determined in equilibrium. If firms cannot change product design, lower buyer search costs for price lead to increased price competition. However, if product design is a decision variable, lower search costs for price may also lead to higher product differentiation, which decreases price competition. In this case, the overall effect of lower buyer search costs for price may even be higher prices, lower social welfare, and higher industry profits. The result is especially interesting because recent technological changes, such as Internet shopping, can affect the market structure through lowering buyer search costs.product design, product positioning, search costs, market structure, endogenous firm decisions, e-commerce

Incoherent magnetization rotation observed in subnanosecond time-resolving x-ray photoemission electron microscopy

We present recent results of time-resolved x-ray photoemission electron microscopy on permalloy microstructures. The stroboscopic experiments feature a time-resolution of Deltatauless than or equal to130 ps. We observe a strong influence of incoherent magnetization rotation processes, leading to a significant transient stray-field formation at the edges of the microstructure. (C) American Institute of Physics

Communication Strategies and Product Line Design

When selling a product line, a firm has to consider the costs of communicating about the different products to the consumers. This may affect the product line design in general, and which products or services are offered in particular. The problem is that firms have to communicate to consumers, possibly through advertising, to make them consider buying the products that firms are selling. This results in the firm offering a smaller number of products than is optimal when advertising has no costs. This effect is greater the extent of consumer confusion about the advertising messages, and is reduced by a greater ability to target advertising. When offering vertically differentiated products (second-degree price discrimination), under general conditions it is optimal to advertise so that one has a greater proportion of sales of a lower-quality product than if advertising had no cost. This situation also allows the firm to charge a lower price for the high-quality product and offer a higher quality of the low-quality product than it would if advertising were without cost.communication strategies, advertising, product policy, product line, segmentation, price discrimination