How to calibrate the thin film sample by varying x and y distance? I want to use my own .8* .8 cm2 thin film sample to calibrate whose magnetization is low( around 1200 emu/cc). I am not getting symmetric M- H loop. I put the sample first in the geoometric center then I vary the x distance so that moment is minimum then I vary y distance. And i choose the y point where the moment is maximum. Can you please suggest me what's the procedure to calibrate the sample having low magnetization?
Post by Lake Shore Cosmin on Feb 7, 2023 12:59:20 GMT -5
Hello, I guess you are referring to saddling or centering the sample and not actually calibrating the moment gain of the magnetometer. You can saddle the sample using a sample with same dimensions but larger magnetic moment, such as a piece of credit card stripe and then substitute with your low moment sample.
Post by Lake Shore Cosmin on Feb 9, 2023 14:32:24 GMT -5
For more guidance on this, see Section 4.3.3. in the 7400-S Series VSM user manual, which shows moment vs. position on all three (X-Y-Z) axes. It explains how much moment is affected by a sample being off-center.
Post by Lake Shore Cosmin on Feb 9, 2023 14:35:35 GMT -5
The sample should be positioned at the geometric center of the pickup coils, a procedure known as "saddling." On a standard electromagnet system, the saddle point is found by finding the local extrema of the moment signal in the x, y, and z directions. Generally, the x (left to right) position should be a local minimum in the moment signal (or its absolute value, to be precise). The y (front to back) position is a local maximum, and the z (up and down) position can be either a maximum or a shallow minimum between two maxima, depending on the separation between the coils. For very weak samples, it is a good idea to saddle using a strong sample (such as a saturated nickel standard), with the same geometry as the weak sample, attached in the same manner as the weak sample to be tested.
It sounds like you're on the right track! For low magnetization samples, achieving a symmetric M-H loop can be challenging. Try adjusting the x and y distances step by step by following PDR tutorial, ensuring you're within the linear range of your setup. Experiment with different field strengths and demagnetization cycles. Patience and multiple trials will help fine-tune your calibration.