In this article, the recording physics of a ring head with a single layered perpendicular medium (Ring/SL) is studied and the results are compared with a single pole head with a double layered perpendicular medium (SPT/DL) by using various simulations and experiments. The Ring/SL has much lower effective medium coercivity than the SPT/DL due to the substantial longitudinal field component of ring head and the incoherent rotation mode of medium magnetizations. Furthermore, switching time of the Ring/SL is estimated as only 10%∼30% of the SPT/DL. In the Ring/SL, the head field gradient of 40 Oe/nm is enough for maximizing SNR. The Ring/SL shows very low noise characteristics especially at high linear density. The signal output of the Ring/SL is smaller than the SPT/DL, but it is large enough to be detected. Therefore, it can be concluded that the combination of single layered perpendicular medium and ring head is highly promising for ultrahigh density recording.
In this article, the effect of thermal fluctuations on switching field at short and long time scales have been investigated by micromagnetic simulation with the Langevin and the time-temperature scaling methods. When the film thickness and/or the aspect ratio are reduced, the switching field decreases substantially owing to the decrease of shape anisotropy and the increase of thermal fluctuation. In the soft magnetic film with a dimension of 0.4 μm×0.2 μm×1 nm, the calculated switching field at a pulse width of 10 ns is 32 Oe, but estimated retention time is less than 1000 s. In such a thermally unstable film, thermally activated switching of magnetization occurs by complex behaviors with creations and annihilations of small and slightly tilted magnetic clusters.
Liquid crystal molecules with a new fluoro‐isothiocyanate moiety were synthesized. They showed remarkably high TNI (>190 °C), wide mesophase range of 170 °C, high dielectric anisotropy (>14) and high optical anisotropy (>0.28). New LC Mixtures of the high TNI (>85 °C) was blended with the novel fluoroisothiocyanate containing LC molecules, phenylcyclohexanes, bicyclohexanes and ester compounds. The LC mixtures show a fast speed (<10ms) of the below one frame rate in 17″ WXGA panel.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.