AN ALTERNATIVE APPROACH TO VECTOR VIBRATING SAMPLE MAGNETOMETER DETECTION COIL SETUP

Vector vibrating sample magnetometers (VSMs) can present problems with respect to angular dependent calibration and positional dependency wh en they are used for measurements on thin film samples, which have dim ensions comparable to or larger than the sample-coil distances. The pr oblems are due to the fact that in conventional VSMs the sample is rot ating with respect to the coils, when performing angular dependent mea surements. In this article a solution is presented based on a setup of VSM detection coils, whose position is linked to that of the sample. Together with a newly designed sample holder, the above mentioned prob lems are prevented or reduced. The vector detection coil system shows a relatively small error in the determination of the magnetization vec tor (+/-1% in the absolute value and +/-0.6 degrees in the angle). Fur thermore, it has a relatively small positional dependency (1% per mm) combined with a sufficient sensitivity (1 nA m(2) or 1 mu emu at 10 s time constant) and a capability of using samples up to 10X10 mm(2). Th e improved sample holder for thin film measurements reduces positional problems while, at the same time, reducing the background signals of the holder (to 10 pA m(2) per kA/m or 7.958X10(-10) emu/Oe). (C) 1998 American Institute of Physics. [S0034-6748(98)04008-8]