Download RSO Measurement Position

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.