Abstract: Ferromagnetic nanoparticles which are converted from paramagnetic, antiferromagnetic, ferrimagnetic or weak ferromagnetic nanoparticles by incorporation of a dopant, the dopant having a concentration less than 0.5%. Major changes occur in the magnetic properties of the host material. A weak paramagnetic material such as Mn3O4 is been converted to a ferromagnetic material that has a Curie point beyond 700° C. and shows almost temperature independent coercivity and magnetic moment. These ferromagnetic nanoparticles can be used as contrast agent, as a vehicle for targeted drug delivery, high temperature magnets, high density magnets, magnetic circuits and many more devices utilizing local interaction of the magnetic field.

Abstract: A process for the production of metal oxide nanocrystalline phosphors activated with a rare earth, line emitting, element. The nanocrystal oxides are produced by a sol-gel like process. The process begins with an n-butoxide solution of the host and activator which is first subject to acetolysis which will cause the pH of the solution to change from basic to acidic. This is followed by the addition of water in a hydrolysis step which forms a host/activator hydroxide solution. To the host/activator hydroxide solution, sodium hydroxide, which is very basic, is added, which will cause the precipitation of host oxide nanocrystals activated with the activator. The host/activator n-butoxide precursors may be synthesized by azeotropic distillation.

Abstract: Electronic displays including CRTs and projection TV (PTV), field emission displays (FED), plasma and electroluminescent (EL) displays, all of whom involve the use of luminescent materials (active displays) for the transfer of information to an audience. The phosphor material used in these displays comprises doped nanocrystals; tiny, separated particles of the order of 100 angstroms or less and thus exhibiting quantum-confined properties. These quantum-confined particles of certain luminescent materials when doped with an activator yield ultra-fast and efficient phosphors. The resultant displays will possess high brightness and high resolution. In addition, certain of the displays will exhibit digital control and increased gray scale.

Abstract: An efficient and ultrafast sensor for X-ray and UV radiation based on doped nanocrystals. These doped nanocrystals consist preferably of impurity-activator doped wide band gap II-VI semiconductors. They yield high efficiency and short recombination time radiation-sensitive phosphors which in response to radiation emit visible light easily detected by conventional sensors such as Si sensors. The combination of pulsed UV/X-ray sources with efficient and ultrafast sensors will yield sensors with increased signal to noise ratio. In a preferred embodiment, thin films of doped nanocrystals are used for generating visible radiation, which can be imaged with a conventional Si-based camera. Other applications also include the use of doped nanocrystals of piezoelectric materials to sense pressure, of pyroelectric materials to sense heat, and of ferroelectric materials to sense electric fields.

Abstract: A glowing device comprises a substrate which is substantially transparent to radiation in a first spectral region and supports a nanoparticle or nanocrystal active layer, which is a thin layer constituted of separated tiny particles with nanometer dimensions, typically 100 .ANG. or less in size. When the nanocrystal layer comprises one of certain luminescent materials activated with certain activators, the layer when excited will efficiently emit radiation characteristic of the activator. Since the particles making up the active layer are very small, the layer can be made very thin, of the order of 1000 .ANG. or less. With this small thickness, the layer will be substantially transparent to radiation except for a narrow range of radiation capable of being absorbed by the active layer and thus capable of exciting the nanocrystal layer. When thus excited, the active layer will emit radiation in a narrow wavelength range.

Abstract: An optically-pumped or electron-beam-pumped solid-state laser employing as the phosphor material doped nanocrystal particles which as a result of quantum confinement can be caused to exhibit discrete levels in its conduction band that can overlap with the corresponding levels in the doping activator such that resonant energy transfer of excited carriers from the conduction band of the phosphor host to that of the activator will occur. The energy levels in the activator are such as to allow very fast carrier transitions to an intermediate level and a slower radiative transition to a ground state. The result is an energy level structure similar to that of a four-level laser but capable of more efficient conversion of the pumping energy to photon generation.

Abstract: An improved AC susceptometer and methodology for its use which is particularly suitable for the characterization of the properties of superconducting materials. Added to the circuitry of a conventional AC susceptometer is frequency domain analytical equipment for measuring the induced magnetic response. The addition of frequency domain measuring equipment permits the determination of the harmonic components of the induced magnetic response. The measurement of the harmonic components of the response also provides novel methodology for studying the phenomena of flux penetration, flux pinning and movement and permits the measurement of parameters such as lower critical field, critical temperatures, and the irreversibility line.

Abstract: An improved AC susceptometer and methodology for its use which is particularly suitable for the characterization of the properties of superconducting materials. Added to the circuitry of a conventional AC susceptometer is frequency domain analytical equipment for measuring the induced magnetic response. The addition of frequency domain measuring equipment permits the determination of the harmonic components of the induced magnetic response. The measurement of the harmonic components of the response also provides novel methodology for studying the phenomena of flux penetration, flux pinning and movement and permits the measurement of parameters such as lower critical field, critical temperatures, and the irreversibility line.

Abstract: Superconducting oxides in the A, B, Cu oxide ternary system, where A is yttrium or a rare earth and B is an alkaline earth, are formed as thin films on a substrate by a sol-gel technique.

Abstract: Apparatus and methodology for mapping the superconductive properties of a sample of superconducting material. The material is cooled so that it is a mixed state and an alternating magnetic field is induced in a portion of the sample to be tested. The harmonic component of the induced alternating magnetic response is measured at a location proximate to the point of induction. As the inducing and measuring devices are displaced relative to the sample the measured amplitude of the harmonic component is stored in suitable storage means as a function of location in the sample. Thus, a map of the superconducting properties of the sample may be generated.

Abstract: Apparatus and methodology for the rapid and inexpensive characterization of superconducting materials. The method and apparatus induces an alternating magnetic field in the sample to be tested. If the material is a superconductor odd harmonics are generated in the alternating magnetic response of the material near the transition temperature. The superconducting transitions are manifested by a peak or peaks in the odd harmonic components of the alternating magnetic response as a function of temperature. The peaks of the harmonic components are detected to indicate the presence and number of superconducting transitions.

Abstract: Luminescent thin films are produced by a sol-gel process in which a gellable liquid is applied to a substrate to form a thin film, gelled and heated to remove volatile constituents and form a polycrystalline luminescent material.

Abstract: An information recording medium uses a semiconductor film on a plastic substrate for obtaining a direct read after write digital recording with laser recording and writing devices. The writing laser produces an area of generated heat in the semiconductor film which produces a heated region in the underlying plastic substrate. The heated plastic substrate material decomposes or degases yielding gaseous components with a high pressure that will burst the overlying semiconductor layer leaving a pit or hole in the reflective surface.