Abstract: The present disclosure relates to optical fiber coupling systems and methods of coupling optical fibers across and with a magnetic field.

Abstract: Disclosed herein is a method and system for measuring magnetoelectric susceptibility. The system includes a magnet supplying a DC magnetic bias to a magnetoelectric sample, an AC drive coil applying an AC magnetic field to the magnetoelectric sample, a charge amplifier amplifying an electric charge signal of the magnetoelectric sample oscillating by the AC magnetic field, and a phase sensitive detector detecting the voltage signal produced by the charge amplifier while supplying induction current to the AC drive coil. Accordingly, it is possible to provide a highly sensitive system for measuring magnetoelectric susceptibility, which is essential for research on multiferroic and magnetoelectric bulk and thin film materials at room temperature, and can also operate in the physical property measurement system (PPMS, manufactured by Quantum Design Co., Ltd.) for measurements under low temperature and high magnetic field environments.

Abstract: A method of searching for a material fated to generate an interband phase difference soliton includes the steps of generating an AC in a soliton candidate material, identifying a loss of AC magnetic susceptibility of the siliton candidate material due to a turn and a twist cut of a vortex line and judging whether or not the soliton candidate material is capable of generating soliton.

Abstract: A scanning microscope for high resolution current imaging by direct magnetic field sensing of a sample maintained in an ambient environment. The scanning microscope uses a magnetic sensor such as a SQUID and a fiber probe magnetically coupled between the SQUID sensor and the sample under study. The fiber probe has a sharply defined tip for high resolution probing and for reaching minute cavities on the surface of the sample. The coupling between the tip of the fiber probe and the sample is controlled by a distance control mechanism, in the range of 1-100 nm. The material of the fiber probe with high permeability and low magnetic noise is chosen to optimize flux transmission to the magnetic sensor. Magnetic coupling to the sensor is maximized by keeping the distance between the end of the fiber probe and the sensor to approximately 0-100 ?m. The fiber probe is integrated into the fiber holder for easy replacement of the fiber probe.

Abstract: A superconducting magnetic field generating apparatus includes a superconducting body for generating a magnetic field below a critical temperature of the superconducting body, a thermal insulation vessel having a space for accommodating the superconducting body, and a ferromagnetic body for adjusting a magnetic field distribution generated from the superconducting body wherein at least a part of the ferromagnetic body is disposed around the superconducting body and a magnetic circuit is formed so as to form the magnetic field distribution in a common side of the superconducting body and the part of the ferromagnetic body.

Abstract: An analytical method and apparatus using principal component analysis of nuclear magnetic resonance (NMR) data for rapid molecular structure/function pattern recognition. The presence of a molecular substructure in an organic compound is determined by comparing principal components calculated from chemical shift values of the substructure in selected compounds with those calculated from the chemical shift values of the organic compound. Alternatively, principal components are calculated from the intensities of NMR signals for a full spectrum, or selected regions thereof, to determine whether an organic compound belongs to or is excluded from a set of structurally related compounds. Also, the presence of a pharmacophore in an organic compound can be determined by comparing the principal components derived from data on a set of compounds known to bind to a particular receptor, or have a common biological effect, with the principal components of the data set of the organic compound.

Abstract: A nondestructive inspection apparatus having a SQUID is made with compact configuration and is capable of detecting a metallic or non-metallic metal for defects, corrosion, and the like, by forming the SQUID and a magnetic field applying coil on the same substrate. The SQUID comprises two Josephson junctions, a washer coil connected to the Josephson junctions to form a superconducting loop, shunt resistors, a damping resistor, and a feedback modulation coil, all of which are formed from a superconducting thin film on a supporting substrate. A magnetic field applying coil is formed on the same supporting substrate with a superconducting thin film or a normal conducting metal thin film. The magnetic field applying coil, which generally has plural turns around the SQUID, applies a dc or ac magnetic field to a sample. The change in magnetic field caused by a defect in the sample is detected by the washer coil, and the position and size of the defect may thus be determined.

Abstract: A superconductive magnetoresistor has a substrate, a ceramic superconductive film which is formed on one face of the substrate, ferromagnetic elements for focusing an external magnetic field, and an insulating film. One of the ferromagnetic elements is integrally combined with the other face of the substrate. The other of the ferromagnetic elements is combined with the ceramic superconductive film thorough the insulating film.

Abstract: The device includes a first body (1) of superconducting material placed in the magnetic field to be measured, an arrangement (7) suitable for successively changing the temperature of this first body above and below its transition temperature, at a first frequency, so as to generate field variations in the vicinity of the body, and an arrangement for determining the field from these variations. The arrangement includes a second body (4) of superconducting material, placed in the vicinity of the first body (1), an optical fiber (8) suitable for changing the temperature of at least one portion of this second body, above and below its transition temperature, at a second frequency greater than the first frequency, in order to generate, in this second body, current variations proportional to the field variations. These current variations are then measured and the field is determined from these variations.

Abstract: A Josephson junction apparatus comprises a polymeric film having flexibility, and a Josephson junction circuit formed on the polymeric film. The Josephson junction circuit includes a Josephson junction device and a wiring for connecting to the Josephson junction device. Namely, the Josephson junction apparatus has flexibility, and thus the Josephson junction apparatus can be placed not only on a flat surface but also it can be placed on a curved surface in practice. Furthermore, in the Josephson junction apparatus, when a functional polymeric film is used as a substrate of a Josephson junction of the Josephson junction device, a protective film is previously formed over the functional polymeric film, so that a wetting of the functional polymeric film, which is caused by water or organic solvents being used repeatedly during the manufacturing process, can be prevented and a dimensional stability of the film can be increased.

Abstract: A fiber optic system detects temperature transients in a superconducting magnet. A signal optical fiber is placed in function proximity with the superconducting magnet for responding to a temperature transient condition and a reference optical fiber is remote from the signal optical fiber. A coherent light outputs coherent light for input to the signal and reference optical fiber to provide a phase shift of about 90.degree. to the coherent light in the signal or reference optical fiber. In one embodiment, a low pass filter provides feed back to the phase modulator to stabilize the modulation while a high pass filter passes temperature transient signals to a suitable analyzer, such as a digital storage oscilloscope, or the like.

Abstract: An apparatus of sensing a magnetic field using a ceramic superconductor magneto-resistive element having a superconductor magneto resistive effect of non linear characteristic against the applied magnetic field, there is provided a coil for applying a bias magnetic field to the magneto-resistive element, the coil is connected to a feed back power source for supplying current for holding the output of the magneto-resistive element constant value, whereby the applied magnetic field is measured by the current supplied to the coil.There is disclosed also a device for sensing a magnetic field using a magneto-resistive element comprising a superconductor member having weak coupling grain boundaries, said device comprising means for applying A.C. bias magnetic field to said element, and means for taking out an output voltage of the element generated by application of the bias magnetic field as the signal representing the intensity of the applied magnetic field.

Abstract: A superconducting circuit system comprises a biasing circuit for producing a bias current that changes periodically, and a superconducting rectifier circuit driven by the bias current. The superconducting rectifier circuit is supplied with a first pulse train including therein positive and negative pulses in synchronization with the bias current and produces a second pulse train of unipolar pulses in response to a transition of a Josephson junction caused by the pulses of the first pulse train.

Abstract: The superconductor magneto-resistive element 14 is installed in a center portion surrounded by two coils 15 and 16 which generate A.C. and D.C. bias magnetic fields respectively. The coils 15 and 16 are respectively connected to A.C. and D.C. power sources for applying A.C. and D.C. bias magnetic field to the element 14.With the output signal of the element 14, the fundamental component having the frequency component same as that of the A.C. bias magnetic field and the quadratic harmonic component having the frequency component twice as that of the fundamental component are calculated using the Fourier transform. The calculated value of the fundamental component is divided by the value of the quadratic harmonic component, thereby removing the change of the output signal of the element 14 due to the fluctuation inherent in the element 14, enabling to measure an external magnetic field with high accuracy.

Abstract: This invention provides a superconducting magnetic shield and a magnetic shielding apparatus including the same, thereby accurately measuring an extremely weak magnetic field such as magnetoencephalographic waves by reducing the influence of magnetic field of the earth or magnetic noises.

Abstract: A magnetic field measurement system including a pick-up coil is not moved but fixed. Strips of superconducting material are arranged in a plane with narrow slits between the strips. The strips are moved very near the pick-up coil along the plane. From output variations of a SQUID magnetometer during the movement, a magnitude of a static field perpendicular to the plane of the strips is obtained.

Abstract: A magnetic field distribution measuring apparatus for measuring an external magnetic field distribution includes a substrate made of a nonmagnetic material and having opposite surfaces, a plurality of magnetoresistive elements deposited on one surface of the substrate and each made of a superconductive material having a weak coupling at the grain boundaries. Coils are provided on the other surface of the substrate at positions corresponding to the magnetoresistive elements. The coils are sequentially applied with AC current to produce AC magnetic field having a peak value greater than a magnetic field threshold level at which the magnetoresistive element changes the state from a superconductive state to a magnetoresistive state. Detecting the degree of magnetoresistive from each magnetoresistive element, the magnetic field distribution can be detected.

Abstract: A superconductive magneto-resistive device for use in a sensor system for sensing an external magnetic field which is formed so as to have a predetermined pattern for a current path through which a supplied current flows. The pattern includes portions formed close and parallel to each other so that magnetic fields induced by respective currents flowing through the portions can be cancelled with each other.

Abstract: An apparatus for magnetic measurement using superconductive magneto-resistive film which is disposed in a magnetic field with the surface of the superconductive magneto-resistive film directed in parallel with the direction of the magnetic field so that the magnetic hysterisis property of the film can be avoided and the accuracy of the measurement can be much improved.

Abstract: A ceramic superconductive magneto-resistive element which has weak grain boundaries is highly sensitive to weak magnetic fields. The magnetic field is measured by the use of an electronic circuit. A comparator is used for comparing an output and reference voltage of the element. When there is a difference between the output and reference voltage bias current is used to equalize these voltages.

Abstract: A thin film dc SQUID and its driving electronic circuitry configured with very high symmetry. The SQUID loop is formed with four holes at the respective ends of crossed slits. Each of these holes forms a single turn secondary for symmetrically arranged pairs of modulation coils and signal coils. The geometrical placement of the modulation coil transformers with respect to the signal coil transformers results in a device which nominally has no mutual inductance between the two groups of coils when the SQUID is biased for normal operation. The external driving circuit is configured to preserve the highly balanced nature of the chip and forces equal magnitudes of current to flow in all four of the bias leads.

Abstract: The invention relates to an apparatus and method to detect a magnetic field by measuring the magnetically modulated resistance of a superconductor maintained at its phase transition temperature (T.sub.c).

Abstract: Pickup coils for imaging magnetometers are formed from plural turns of a conductor with varying spacing between turns selected so that the Fourier transform of the coil turns function which is the filter function of the coil, has no zeroes within the spatial frequency bandwidth of the magnetic field generated by a two or three dimensional current to be imaged. Various exemplary coil configurations are presented including a Gaussian distribution for the turns of a planar coil.

Abstract: Device is provided for reading information from a magnetic recording medium, comprising a SQUID (15), a magnetic yoke formed from two flux guides (3 and 5) and a face (13) for magnetic flux coupling of the SQUID with the magnetic recording medium. The SQUID is provided with connection means (33) for a detection circuit (35).

Abstract: In a method for calibrating multi-channel SQUID systems having gradiometers of an arbitrary order, calibration coils, each having the same number of ampere turns are symmetrically arranged at identical distances between the parallel coil planes with respect to every gradiometer coil, so that every gradiometer coil is penetrated by a common, oppositely directed magnetic field generated by the calibration coils. The field that the calibration coils produce at the locations of the gradiometer coils are numerically calculated to obtain a net gradient field value which is divided by the measured voltage at the output of the allocated SQUID electronics in order to calculate the calibration factor.

Abstract: A superconducting current detecting circuit which comprises a reference current generation circuit for generating a reference current and a DC flux parametron circuit for comparing an input current to be detected with the reference current to thereby produce pulses in synchronism with an input excitation signal, the number of the pulses being varied in accordance with a difference between the input current and the reference current, the pulses having positive or negative values depending on the polarity of the difference, the reference current generation circuit having means for increasing or decreasing the reference current by a quantity corresponding to the number of the pulses in response to the polarity of the pulses so that reference current generation circuit produces the reference current which agrees with the input current.