A miniature SQUID magnetometer with direct read-out electronics

A novel miniature SQUID magnetometer with direct read-out electronics has been developed. A high flux-to-voltage transfer factor of up to 2500 mV//spl Phi//sub 0/ is achieved without additional positive feedback (/spl Phi//sub 0/ is the flux quantum). A flux resolution of 8/spl times/10/sup -7/ /spl Phi//sub 0//Hz/sup 1/2 /, corresponding to a magnetic moment sensitivity of approximately 2/spl times/10/sup -2/0 Am/sup 2//Hz/sup 1/2 / has been measured. This magnetometer can be used to study the dynamic magnetization properties (including NMR and MRI) of micron and sub-micron size particles and for high-resolution surface magnetometry.