Effect of crystalline disorder on magnetic switching in small magnetic cells
Abstract I present a study of the influence of disorder in thin magnetic films on the switching behavior of small magnetic cells of well-defined shape and size. The disorder considered arises from randomly oriented crystalline grains of different shape, size, and crystalline orientation which gives rise to locally fluctuating intrinsic anisotropy directions and strengths. The study comprises a theoretical investigation of a disordered Stoner–Wohlfarth model, as well as micromagnetic simulations. I show that the fluctuations in the total anisotropy and therefore in the switching fields are controlled by a single dimensionless parameter. The theoretical findings are well confirmed by micromagnetic simulations of many different samples.
This retrospective study, based on 18 case reports, describes an organic affective syndrome, manic type, occurring shortly after the initiation of thyroid replacement in hypothyroid patients. The symptomatology and homogeneity of the syndrome offers insight into the relationship between thyroid activity and affective disturbance. The patients experiencing mania showed concurrent psychopathology at the time of replacement therapy, frequently had a past history of personal or familial psychiatric disorder and were given dosages in the high range of normal. The potential morbidity of the manic state was considerable. These findings suggest that a group of hypothyroid patients at risk can be identified. In such a group, lower initial dosages and gradual increases in dosage may be indicated.