Existing techniques for characterization of longitudinal recording media using remanence measurements are extended to perpendicular media, in particular to Alumite, and correction for demagnetizing fields is taken into account. It is found that these techniques have limited value because of the sensitivity of the analysis to the correction factor used. Measurement of the recoil lines is investigated as an alternative method of probing the reversal processes.

An investigation of the remanent and hysteretic properties of perpendicular media such as Alumite involves calculation of internal fields which requires the demagnetisation factor to be known. Demagnetisation effects have been calculated for Alumite, which is an ideal model material, by considering it as a hexagonal matrix of columns. This predicts that the demagnetising effects are less than that of a continuous film at saturation but increase as the magnetisation decreases.

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Vector vibrating sample magnetometers ͑VSMs͒ can present problems with respect to angular dependent calibration and positional dependency when they are used for measurements on thin film samples, which have dimensions comparable to or larger than the sample-coil distances. The problems are due to the fact that in conventional VSMs the sample is rotating with respect to the coils, when performing angular dependent measurements. 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 problems are prevented or reduced. The vector detection coil system shows a relatively small error in the determination of the magnetization vector ͑Ϯ1% in the absolute value and Ϯ0.6°in the angle͒. Furthermore, it has a relatively small positional dependency ͑1% per mm͒ combined with a sufficient sensitivity ͑1 nA m 2 or 1 emu at 10 s time constant͒ and a capability of using samples up to 10ϫ10 mm 2 . The 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 7.958ϫ10 Ϫ10 emu/Oe͒.

Demagnetisation compensated torque-and angle-dependent remanence measurements are presented on commercial and experimental metal evaporated tapes. The latter have been prepared in our laboratory on a mini-roll coater system. From these results the easy axes have been determined.