The Effect of Deposition Rate on the Low Temperature Resistivity and the Neel Point of \alpha-Mn Thin Films

Authors: F. BOAKYE, A. D. C. GRASSIE

Abstract: The effect of deposition rate on low temperature resistivity and the Neel point of thin films of evaporated \alpha-Mn has been studied. Resistivity measurements were carried out between 300 and 1.5 K using the van der Pauw four probe technique. A sharp transition, which defines the Neel point of antiferromagnetic Mn, has been observed at 90 \pm1 K by plotting the temperature derivative of the resistivity against temperature for a sample whose resistivity temperature behaviour is typical of bulk \alpha-Mn. The results reveal that, as the rate of deposition increases, the resistivity temperature pattern changes in a way so as to increase the line width of the transition. However, at a deposition rate of 30\AA s^{-1}, the transition is not observed. The excess low temperature resistivity increases as the rate of deposition increases. The origin of these excess resistivities can be interpreted as due to the effect of a marked sensitivity of the magnetic moment of Mn atoms to their local environment.

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