Electronic transport and magnetic properties of Ge1–xMnx / Ge 100 films are investigated as a function of Mn dilution. Depending on x, characteristic temperatures separate different regimes in both properties. Resis- tivity exhibits an insulatorlike behavior in the whole temperature range and, below about 80 K, two distinct activation energies are observed. At a higher temperature value, TR, resistivity experiences a sudden reduction. The Hall coefficient shows a strong contribution from the anomalous Hall effect and, at TR, a sign inversion, from positive to negative, is recorded. The magnetic properties, inferred from magneto-optical Kerr effect, evidence a progressive decrease of the ferromagnetic long range order as the temperature is raised, with a Curie temperature TC not far from TR. The transport and magnetic results are qualitatively consistent with a perco- lation mechanism due to bound magnetic polarons in a GeMn diluted magnetic semiconductor, with localized holes (A. Kaminski and S. Das Sarma, Phys. Rev. B 68, 235210 2003.)

Magnetic and electronic transport percolation in epitaxial Ge1-xMnx films / Pinto, N; Morresi, L; Ficcadenti, M; Murri, R; D'Orazio, F; Lucari, F; Boarino, Luca; Amato, Giampiero. - In: PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS. - ISSN 1098-0121. - 72:(2005), pp. 165203-1-165203-7. [10.1103/PhysRevB.72.165203]

Magnetic and electronic transport percolation in epitaxial Ge1-xMnx films

BOARINO, LUCA;AMATO, GIAMPIERO
2005

Abstract

Electronic transport and magnetic properties of Ge1–xMnx / Ge 100 films are investigated as a function of Mn dilution. Depending on x, characteristic temperatures separate different regimes in both properties. Resis- tivity exhibits an insulatorlike behavior in the whole temperature range and, below about 80 K, two distinct activation energies are observed. At a higher temperature value, TR, resistivity experiences a sudden reduction. The Hall coefficient shows a strong contribution from the anomalous Hall effect and, at TR, a sign inversion, from positive to negative, is recorded. The magnetic properties, inferred from magneto-optical Kerr effect, evidence a progressive decrease of the ferromagnetic long range order as the temperature is raised, with a Curie temperature TC not far from TR. The transport and magnetic results are qualitatively consistent with a perco- lation mechanism due to bound magnetic polarons in a GeMn diluted magnetic semiconductor, with localized holes (A. Kaminski and S. Das Sarma, Phys. Rev. B 68, 235210 2003.)
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11696/31074
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