Search

This paper presents a novel magnetometer based on the Villari effect of a permalloy rod. The Villari effect describes that the magnetic properties of a ferromagnetic sample change when under mechanical stress. Theoretical analysis indicates that the output voltage amplitude of the pick-up coil is proportional to the magnetic field density B in the direction along the length of a rod. The sensor element is composed of a permalloy rod, a small lead zirconate titanate (PZT) plate, and one pick-up coil. A prototype is fabricated and the basic performance of the magnetometer is measured. We solve problems, such as the unreliable, nonrepeatable performance and complex manufacturing process of previous Villari effect-based magnetometers, and achieve better overall performance. With a sensitivity of 18.8 pTrms/\sqrt\rm Hz at 1 Hz, the magnetometer has a nonlinearity error of less than 0.7% at a wide range of 2 \muT and a total noise of 40.3 pTrms from 0.1 to 10 Hz. A working range of 20 \muT is achieved with a nonlinearity error of less than 2.3%. The proposed magnetometer has low inherent noise, low power consumption (only 3.68 mW), a simple structure and signal processing, good linearity, and high resolution . [ABSTRACT FROM AUTHOR]

After a brief description of the double-sided fabrication process, we give an example to show that a quite large array of intrinsic Josephson junctions (IJJs) can be made by superconductively connecting 256 stacks of junctions together. Each of these stacks contains only 40 junctions which prevents problems causing by heating. We present a detailed discussion on a new structure we have developed in which an extra electrode can be fabricated in the middle of an array by a slight modification of the double-sided process. Using this middle electrode, we can determine further in- formation on the physical processes inside the stack than is possible without such an electrode. Finally we shall discuss terahertz generation in IJJs when an external magnetic field is applied perpendicular to the width of the junctions. [ABSTRACT FROM AUTHOR]

Single-crystal whiskers of Y1Ba2Cu3Ox with a length of about 4 mm were grown from an Sb-doped pre- cursor. The optimum nominal composition of precursors in this Sb-doping method is Y2Ba2.75Cu3Sb0.5Ox. Sb is not detected in the whiskers by energy-dispersive x-ray spectroscopy (EDS). The standard 4-probe transport measurements for the as-grown whiskers show a critical temperature Tc of about 90 K and a c-axis critical current density Jc of 9.51 × 104 A/cm² at 89 K. [ABSTRACT FROM AUTHOR]