Detection of Current Distribution in Bulk Samples With Artificial Defects From Inversion of Hall Magnetic Maps

Abstract

A two-sided inverse Biot-Savart algorithm for the computation of critical current distributions in High Temperature Superconductor (HTS) pellets is introduced. It is based on simultaneous measurement of the magnetic field on top and bottom of the bulk sample with a double Hall probe, and the authors' discretization and QR inversion scheme. It yields current maps which are detailed in the ab-plane for each half of the bulk sample along the c-axis. The computed current is a O(1/z)-weighted average of the real current along the c-axis over each slice. This is the best possible resolution for current maps along the c-axis, regardless of inversion scheme.We demonstrate the new procedure by analyzing a non-c-homogeneous simulation and a real HTS pellet of cylindrical geometry with asymmetrically drilled holes on both faces.Index Terms-Critical current maps, hall magnetometry, HTS bulk samples, inverse Biot-Savart problem.

Chemical Solution Deposition of Insulating Yttria Nanolayers as Current Flow Diverter in Superconducting GdBa2Cu3O7−δ Coated Conductors

“…Therefore, the possibility of oxygen annealing the Y 2 O 3 /GdBCO bilayer below 500 °C was tested in different samples for a variety of profiles. The subsequent evaluation of these profiles was performed by measuring the perpendicular trapped field B z after field cooling the samples in liquid nitrogen. , Unfortunately, for all temperature profiles below 500 °C, the inhomogeneous distribution of B z indicated an incomplete oxygen loading of the GdBCO layer. This temperature limitation is illustrated by the B z ( x , y ) map in Figure , where a 110 × 12 mm 2 CC sample was oxygen annealed in a single temperature step of 450 °C for 48 h. Even after 48 h, the homogeneity across the width ( x -axis) and the length ( y -axis) was unsatisfactory for performing transport current tests.…”

Physical principles of development of magneto-levitation systems based on the second generation high temperature superconducting composites (Review)

“…To perform direct transport measurements it is required to cut rectangular bars that could result in mechanical cracks and, as a consequence, errors of determination of J c . Other method, which is applied more frequently refers to mapping of captured magnetic flux after application and release of the magnetic field (permanent or pulsed) with further calculation of the critical current density by means of the inversion operation [16,17].…”

Физические Принципы Создания Магнитолевитационных Систем На Основе Высокотемпературных Сверхпроводящих Композитов Второго Поколения (Обзор)

“…Для проведения прямых транспортных измерений необходимо вырезать прямоугольные бруски, что может привести к появлению механических трещин и, как следствие, ошибкам в определении J c . Другой способ, который применяется чаще -картографирование захваченного магнитного потока после приложения и снятия магнитного поля (постоянного или импульсного) с последующим расчетом плотности критического тока с помощью операции инверсии [16,17].…”