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A method for calibrating the force gradients and probe magnetic moment in phase-contrast magnetic force microscopy ͑MFM͒ is introduced. It is based upon the combined electrostatic force microscopy EFM and MFM images of a conducting non magnetic metal strip. The behavior of the phase contrast in EFM is analyzed and modeled as a finite area capacitor. This model is used in conjunction with the imaging data to derive the proportionality constant between the phase and the force gradient. This calibration is further used to relate the measured MFM images with the field gradient from the same conducting strip to derive the effective magnetic moment of the probe. The knowledge of the phase-force gradient proportionality constant and the probe's effective moment is essential to directly quantify field derivatives in MFM images.

Soft-x-ray appearance-potential spectra of rare-earth elements are interpreted in terms of strong resonance interactions between the incident electrons and atomic 4/ states. These interactions account for both the large intensity and the threshold shifts of the measured signal. This resonance persists in La, Ce, Pr, arid Nd when present as only a few atomic percent in a NiCr alloy reflecting the local character of the interaction.

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