Leakage current measurements are performed on prototype cells revealing an S-shaped current versus voltage curve. This result indicates the presence of ion generation and recombination in the liquid crystal bulk. The compensation of the electrical field and the saturation current are related to the alignment layer thickness and to the temperature. The slope of the I–V curve corresponds with Onsager's dependency of the ion generation. The time dependency of the current is modelled by an empirical fitting of the generation constant. A complete theoretical model is thus presented. The simulation fits with the measurements and gives a profound insight in the long term ion transport in nematic liquid crystal displays.

AbslrscL ?he elfeclive magnetic permrabilily I L and effeclive dielectric mnstant L are two equally important quantities for the ~liaraclrrizntion of elec~romagnelic properties of "nporilrs. For granular femmagnelic melals, however, the presence of permanen1 magnetic moments means that lhe Munvrll-Game11 theory Is inapplicable lo the cillculalion OC effective I,. By extending the approach 4 Onsager, we derive a simple qualion for ~r wllose numerical mlulion in lhe case of granular Ni sl~ows significant devinlion from unity in far-infnrcd and microwave frequencies. The kl~aviour of 1, is prcdiclrd to I* a semilive function of pmicle Size and temperature, thus making the malerial pentinlly uuhlr as an ahwrhrr of far-infrared or micmvavc ndiation.

Prototype liquid crystal cells with different alignment layers were studied at different temperatures. Long-term leakage current measurements were then performed revealing an S-shaped IVcurve typical for the presence of ion generation and recombination as well as the Onsager's dependency. Highly and weakly resistive alignment layers can be clearly distinguished.