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Table 3. Summary of Functions of Measurement Position in RSO Center Position Center position is the center of the pick up coils. The sample will oscillate around the centering position. Maximum Slope Position The maximum slope position is above the center of the SQUID pickup coils and is the steepest, most linear part of the SQUID voltage v.s. position curve. The distance between the center of the pickup coils and the maximum slope is defined by the “Longitudinal Position Offset” (logged to diagnostic file) Advantages: Keep the sample position properly located by fitting to a relatively long, centered travel path. Accommodate to sample position changes. Any measurements you take can be absolutely accurate. Compatible with both the iterative reg. (default) and the linear reg. (when iterative reg. fails due to tolerance) algorithm. Together with large amplitude, one can illustrate the entire SQUID response curve. Advantages: Can span as little as 2mm of the sample motion rang. This will make the sample feel less magnetic field variation, typically <0.001%. Small amplitude allows higher frequency oscillations, faster measurements. Large response due to the steepest slope. Allow resolution of magnetic moments that are well below the limit of most other instruments. Disadvantages: Disadvantages: Only oscillates through a small section of Measurement is relative slow. the pick-up coil -> less accurate than a When oscillation amplitude is large and center position or conventional DC. iterative reg is selected, fitting can fail due Cannot use auto-tracking or the iterative to low tolerance. reg. algorithm. Not good when sample position is drifting (not good for temperature scan) When to use: M v.s. T When to use: M v.s. H Suggested Parameters: Suggested Parameters: Amplitude 0.5-1.0 cm Amplitude 3-5 cm Number of Cycles 15-60 Number of Cycles 5-15 Position Maximum Slope Position Center Frequency 4 Hz Frequency 1 Hz Algorithm Linear Regression Algorithm Iterative Regression * Content in table can be found in MPMS XL OPTIONS MANUALS -> Reciprocating Sample Option (RSO) -> Page 4-15.