Magnetoresistance of Mn:Ge ferromagnetic nanoclusters in a diluted magnetic semiconductor matrix

Park, Y. D.; Wilson, A.; Hanbicki, A. T.; Mattson, J. E.; Ambrose, T.; Spanos, G.; Jonker&hthinsp;, B. T.
April 2001
Applied Physics Letters;4/30/2001, Vol. 78 Issue 18, p2739
Academic Journal
We have fabricated a thin film magnetic system consisting of nanoscale Mn[sub 11]Ge[sub 8] ferromagnetic clusters embedded in a Mn[sub x]Ge[sub 1-x] dilute ferromagnetic semiconductor matrix. The clusters form for growth temperatures of ∼300 °C with an average diameter and spacing of 100 and 150 nm, respectively. While the clusters dominate the magnetic properties, the matrix plays a subtle but interesting role in determining the transport properties. Variable range hopping at low temperatures involves both nanoclusters and Mn[sub Ge] sites, and is accompanied by a negative magnetoresistance attributed in part to spin-dependent scattering analogous to metallic granular systems. © 2001 American Institute of Physics.


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