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AssigneeU.S. Philips Corporation
InventorsOlivier O. Kahn, Charlotte Jay, Jonas Krober
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Chemical substances are provided which exhibit thermally induced spin transitions between two stable spin states at ambient temperature, said transitions being associated with a hysteresis phenomenon and resulting in an abrupt variation of the color of the molecules for realizing a medium for storing, processing and/or displaying information by way of thermal writing, optical reading and thermal erasing, a particular embodiment of such a medium comprising at least a layer of chemical substances including a lattice with a molecule comprising a metallic element Fe.sub.(II), or Fe.sub.(III) or Co.sub.(II) associated with at least one ligand chosen from the substituted triazoles which are defined by the formula: ##STR1## in which R is H or an alkyl C.sub.n H.sub.2n+1 or R is an amine group NL.sub.2 where L is H and an alkyl radical, said molecule also comprising one or several anions chosen, for example, from BF.sub.4.sup.-, ClO.sub.4.sup.-, Br.sup.-, Cl.sup.-, and the lattice containing a defined quantity of non-ligand water, ensured by the presence of a hygroscopic substance.
A method of preparing a medium for storing, processing and/or displaying information by thermal writing, optical reading and thermal erasing, which medium is addressable, eraseable and re-addressable with data, wherein chemical substances are provided which exhibit thermally induced spin transitions between two stable spin states at ambient temperature, said transitions being associated with a hysteresis phenomenon and resulting in an abrupt variation of the color of the molecules of the chemical substances,
A method of preparing a medium for storing, processing and/or displaying information wherein at least one layer is provided of chemical substances comprising metal-ligand complexes exhibiting thermally induced spin transitions between two stable spin states at ambient temperature, said transitions being associated with a hysteresis phenomenon and resulting in a variation of the metal-ligand bond length and an abrupt variation of the color of the molecules of the chemical substances,
A method for preparing a medium for storing, processing and/or displaying information which comprises providing on a support at least one layer of a chemical substance which exhibits a hysteresis phenomenon, wherein the chemical substance comprises:
A method for preparing a medium for storing, processing and/or displaying information comprising providing chemical substance which exhibits a hysteresis phenomenon, wherein the chemical substance comprises:
A method for preparing a medium for storing, processing and/or displaying information which comprises providing on a support a chemical substance which exhibits a hysteresis phenomenon, wherein the chemical substance comprises:
Dependencies are inferred from the claim text.