We describe a new type of scanning probe microscope based on a superconducting quantum interference device (SQUID) that resides on the apex of a sharp tip. The SQUID-on-tip is glued to a quartz tuning fork which allows scanning at a tip-sample separation of a few nm. The magnetic flux sensitivity of the SQUID is 1.8 μΦ(0)/√Hz and the spatial resolution is about 200 nm, which can be further impr...

We report the creation of a pair of Josephson junctions on a toroidal dilute gas Bose-Einstein condensate (BEC), a configuration that is the cold atom analog of the well-known dc superconducting quantum interference device (SQUID). We observe Josephson effects, measure the critical current of the junctions, and find dynamic behavior that is in good agreement with the simple Josephson equations ...

This paper describes a superfluid analog of the superconducting RF SQUID.1 Whereas an RF SQUID is sensitive to magnetic flux, the 4He SQUID (Superfluid QUantum Interference Device) is sensitive to absolute rotation. The device described here exhibits several of the characteristic phenomena of SQUIDs. For example: There is a "staircase" response function. The slope of the staircase response is d...

Abstruct-The suppression of the critical current in YBCO Josephson junctions by the Earth's magnetic field strongly affects the operation of SQUIDs outside magnetic shielding. Commonly, one observes a modulation of the SQUID fluxvoltage transfer function amplitude, Vsq.pp, with a period of AB,, leading to an increased white flux noise level or unstable SQUID operation. Here, we report on the in...

Squid and other cephalopods catch prey with remarkable speed and precision [1]. Before the strike occurs, they encounter the difficult task of judging an object's distance and size in the contrast-poor world of the mid-water environment [1-4]. Here we describe a solution to this common problem underwater, where a large portion of a squid's dorso-temporal retina is intentionally blurred. This ap...

Magnetic immunoassays utilizing magnetic marker and high Tc superconducting quantum interference device (SQUID) have been performed. In this magnetic method, binding-reaction between an antigen and its antibody is detected by measuring the magnetic field from the magnetic marker. First, we discuss the magnetic property of the marker, and show that Fe3O4 particles with diameter of 25 nm can be u...

Lobster and squid giant nerve fibers respond differently when subjected to osmotic challenges. The axons proper, as distinct from the total (fiber) complex formed by the axon and connective sheath, both behave as "fast" osmometers for changes in the concentration of NaCl, but the maximum degree of swelling in hyposmotic media is by about 60% in lobster and only by 20% in squid. The relative vol...

A thorough investigation has been made to obtain SQUID device parameters and properties, and the optimization of the latter for the application of logics gates. SQUID OR, AND gates have been designed theoretically using the optimized techniques. Our concept of turn-on delay has been applied for critically ascertaining the switching speed of these logic gates. The dynamic response of the logics ...