Interactions in Nanoscale Arrays of Soft Magnetic Bi-Layers
Magnetic bi-layers are becoming increasingly popular as a medium for perpendicular patterned media. In order to understand the net interactions between the layers and between adjacent magnetic elements in an array, we use a coupled Preisach model to model the hysteresis loops we measured for a sample consisting two magnetically soft layers of FeCoTaZr, separated by an 0.8-nm Ru spacer layer. The model reproduces the major hysteresis loop to decent agreement. The model was then decoupled to reveal the reversal behavior of the individual layers. This paper demonstrates that coupled Preisach modeling of the hysteresis loop is an effective tool to analyze such interacting material systems.
Exchange coupled composite media for perpendicular magnetic recording
Exchange coupled composite (ECC) media has been shown to possess several major advantages relative to conventional perpendicular media, including a reduction in the switching field of approximately a factor two for the same thermal stability and greater insensitivity to easy axis distribution. In this paper, full magnetostatic interactions are included: this allows comparison between the behavior of multigrain thin films and that of isolated grains as presented earlier. Significant results include hysteresis loops for thin films under various conditions including inadequate and excessive intra granular exchange between the hard and soft materials. An important distinction is made between the coercivity and remnant coercivity as a function of angle between applied field and easy axis. A perpendicular magnetic recording head is used to compare the shape of effective fields for ECC and conventional perpendicular media. Written transitions in the ECC media appear to be similar to those written in perpendicular media at comparable densities.
ARRESTS AMONG HOMELESS AND RUNAWAY YOUTHS: THE EFFECTS OF RACE AND GENDER
ABSTRACT This study examined the contributions of race and gender to the likelihood of a first post-run arrest for a more serious and less serious offense in a sample of homeless and runaway youths from four Midwestern states. Event history analysis was used to test the hypothesis that race and gender would interact so that the likelihood of a first post-run arrest for a more serious and less serious offense would be highest for non-white males and non-white females, respectively. Potentially confounding factors—deviant subsistence strategies, substance use, gang involvement and membership, prior arrests, age, prior physical abuse, age on own, and spending time on the street—were controlled in the analyses. The hypotheses regarding the interaction of race and gender were not supported by the data. Non-whites were more likely than whites, and males were more likely than females, to be arrested for a more serious offense, and white females were more likely than non-white females to be arrested for a less serious offense.