Limitations of measuring small magnetic signals of samples deposited on a diamagnetic substrate

Journal of Magnetism and Magnetic Materials

Volumn 320, Issue 23, 2008, Pages 3341-3346

  Ney, A ^a   Kammermeier, T ^a   Ney, V ^a   Ollefs, K ^a   Ye, S ^a  

^a UNIVERSITY OF DUISBURG ESSEN   (Germany)

Author keywords

Dilute magnetic semiconductor; SQUID magnetometry

Indexed keywords

MAGNETIC MEASURING INSTRUMENTS; MAGNETOMETERS; SQUIDS; SUPERCONDUCTING MAGNETS;

DILUTE MAGNETIC SEMICONDUCTOR; EXPERIMENTAL CONDITIONS; EXPERIMENTAL TECHNIQUES; HIGH SENSITIVITIES; MAGNETIC SIGNALS; SQUID MAGNETOMETERS; SQUID MAGNETOMETRY; SUPERCONDUCTING QUANTUM INTERFERENCE DEVICE;

QUANTUM INTERFERENCE DEVICES;

EID: 53749108440     PISSN: 03048853     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.jmmm.2008.07.008     Document Type: Article

References (16)

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15. The magnet reset option is used at nominally zero magnetic field in our case. The superconducting coil is locally heated up at one spot to quench residual superconducting currents in the coil; resetting the magnet at finite fields is not used here; this procedure generates more heat due to the larger current which can heat up the entire coil to remove trapped flux loops as well. On the other hand, the mangnet needs longer time to settle afterwards. Note that the reset magnet option is different for older and more recent magnets of the MPMS and the manual of the given system should be consulted
16. Alternative explanations for the residual signals could be (i) the electronic control of the power supply for the magnet: there is an auto-correcting system built in (not clearly described in the manual), which can be reset by switching off the control unit (not the Kepco itself); this has to be done, e.g., prior to the zero-current offset calibration procedure. At least in some cases, it appears that such a reset can reduce the residual signal. (ii) Also non-linearities or thermal drifts in the shunt resistors and the respective amplifiers could in principle account for the observed residual signals. The contribution of these artifacts to the residual magnetic signal cannot be corrected in an easy and straightforward manner since they are irreproducible from experiment to experiment