Hall-array gradiometer for measurement of the magnetic induction vector insuperconductors

An experimental technique for measuring the distribution of the normal and planar components of the magnetic induction near the surface of a supercond ucting sample is described. This technique utilizes a design of a double-la yered Hall sensor array fabricated from a GaAs/AlGaAs heterostructure conta ining two parallel layers of a two-dimensional electron gas. Applications o f this technique are demonstrated in measuring the current density distribu tion and in characterizing the flux creep process in a thin YBa2Cu3O7 cryst al. (C) 1999 American Institute of Physics. [S0021-8979(99)31408-0].