Abstract: A torque magnetometer employing integrated piezoresistive levers to measure magnetization of very small anisotropic samples. A sample holding platform is cantilevered from the substrate by parallel legs on which piezoresistors have been applied. A Wheatstone bridge, which includes the piezoresistors, is completely integrated on a magnetometer substrate. Specific output connections are made to the electrical conductors of the bridge in a manner to eliminate Hall effect error signals in an alternative embodiment.

Abstract: A dual capillary inlet cryogenic test chamber having the ability to continuously regulate temperature between about 1.5 K. and 400 K. A controllably heated capillary tube is located in the cryogenic reservoir, spaced from the test chamber and thermally insulated from the cryogen. This capillary tube has a characteristic impedance to fluid flow. A second low temperature, high impedance capillary tube inlet is also in the cryogenic reservoir and is connected between the cryogen reservoir and the test chamber. The combination of a control system with pressure and temperature feedback, combined with the two inlet tubes of different impedance, enables the apparatus to operate continuously and stably at any temperature within its operating range, or to smoothly sweep through any predetermined temperature range.

Abstract: A method for controlling the flow of a cooling medium such as helium into an insulated chamber surrounding a region to establish a stable thermal environment in the region over a wide range of cryogenic temperatures. A thermally insulated capsule surrounds a variable temperature capillary to precondition the helium before it flows into the insulated chamber. The capillary can be operated in different modes, depending upon the heating or lack of heating of the capillary. At low temperatures the capillary can pass the helium in its liquid phase, at high temperatures only a small amount of gaseous helium is passed, and at certain intermediate temperatures there is an ample flow of gaseous helium only.