Magnetization ringing

Today, dynamic random-access memories (DRAMs) are transistor/capacitor-based semiconductor devices, with access times measured in nanoseconds and very low costs. Core memories were made of magnetic rings not less than a millimetre in diameter, so that a megabyte of memory would have occupied square metres, while a corresponding DRAM would occupy a few square millimetres. Another version of a DRAM is the read-only memory (ROM), essential for the operation of any computer, and unalterable from the day it is manufactured. We see that developments in magnetic memories involved dramatic reductions in cost and... 

Finally, we also mention a cobalt ring (37), and the non-magnetic ring Zn C [Zn(hmp)2]6 2+ analogue (38), in which hmp is 2-hydroxymethyl-pyridine. A central octahedral Zn2+ ion is encapsulated in a hexanuclear ring. 

Fig. 6. The local magnetic ring current field Hr of an aromatic molecule. Ho is the external polarizing field. The field strength at a point P is determined by the position relative to the aromatic ring and by the size of Hr. Hr depends on the total number of ji-electrons in the aromatic molecule...

Example Magnetization Ringing in Magnetic Nano-Elements... 

Analysis of this data reveals that the parameters are very similar to those of the monocyclic model compound A -carboxamidopyrazole, but there is a small shielding effect due to contribution of the resonance structures (see Scheme 1), which may be indicative of a small magnetic ring current. The H coupling constants are of similar magnitude to those of simple pyrazoles. The chemical shift of the carbonyl carbon appears in the amide rather than in the ketone region. 

Fig. 23. Representation of the metal skeleton of the Mo75V2ol-type cluster with the emphasized magnetic ring-shaped band formed by 10 triangles having common...

Nie YR, Li W, An LJ et al (2006) Eabricating ordered 2D arrays of magnetic rings on patterned self-assembly monolayers via dewetting and thermal decomposition. CoUoids Surf A 278(l-3) 229-234... 

There are other ways to decide if a compound is aromatic, of which the magnetic ring current from NMR, and various other spectroscopic methods were all examined. From each of these methods, the result was the same, namely any homoaromatic resonance present in triquinacene was too small to measure. 

Castano, F. J., Morecroft, D., Jung, W., and Ross, C.A. (2005) Spin-dependent scattering in multilayered magnetic rings. 

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