High sensitivity, directional dc-SQUID magnetometer

A method of producing a SQUID magnetometer, comprising:

• depositing a seed layer on a substrate;
• depositing a first buffer layer on the seed layer;
• etching the seed layer and the first buffer layer to form a boundary separating (i) a first portion having the seed layer and the first buffer and, (ii) a second portion where the seed layer and the first buffer are substantially removed, wherein the boundary includes a first part and a second part and wherein the first part of the boundary is not collinear with the second part of the boundary;
• depositing a second buffer layer on the second portion;
• depositing a superconducting material on the first buffer layer and the second buffer layer;
• and
• etching the superconducting material to form a SQUID loop across said boundary thereby forming said SQUID magnetometer, the SQUID loop comprising a plurality of Josephson junctions, wherein
• a first Josephson junction in the plurality of Josephson junctions is defined by the first part of the boundary, and
• a second Josephson junction in the plurality of Josephson junctions is defined by the second part of the boundary.