Very Low Frequency Integrating Vibrating Sample Magnetometer (VLFVSM) with High Differential Sensitivity in High dc Fields

A vibrating sample magnetometer is described which is specifically adapted for magnetic moment measurements in high dc fields. The sample is moved at very low frequencies between series opposing detection coils, the induced voltage is integrated, and each cycle is recorded so that the output can be further time‐averaged. Two novel aspects make this instrument particularly useful for high field measurements. First, the sample is moved beyond the center of the detection coils so that positioning errors, forces, and other incidental effects are eliminated. Second, a precise reference balance voltage is synchronously applied to the output signal to permit high‐resolution differential measurements of magnetic moment. In addition to a detailed description of the basic VLFVSM, a general discussion of flux integration techniques is presented. Operation of the VLFVSM with field modulation superimposed, variable temperature, variable pressure, additional electronic filtering, and under swept‐field conditions is dis...