Magnetic and electronic transport percolation in epitaxial Ge{sub 1-x}Mn{sub x} films

Journal Article · Sat Oct 15 04:00:00 EDT 2005 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PhysRevB.72.165203· OSTI ID:20719643

Pinto, N; Morresi, L; Ficcadenti, M; Murri, R ^[1]; D'Orazio, F; Lucari, F ^[2]; Boarino, L; Amato, G ^[3]

---

1. INFM-Dipartimento di Fisica, Universita di Camerino, Via Madonna delle Carceri, I-62032 Camerino (Italy)
2. INFM-Dipartimento di Fisica, Universita di L'Aquila, Via Vetoio-Coppito, I-67010 L'Aquila (Italy)
3. IEN 'G. Ferraris', Via delle Cacce 91, I-10135 Turin (Italy)

Electronic transport and magnetic properties of Ge{sub 1-x}Mn{sub x}/Ge(100) films are investigated as a function of Mn dilution. Depending on x, characteristic temperatures separate different regimes in both properties. Resistivity 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, T{sub R}, resistivity experiences a sudden reduction. The Hall coefficient shows a strong contribution from the anomalous Hall effect and, at T{sub R}, 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 T{sub C} not far from T{sub R}. The transport and magnetic results are qualitatively consistent with a percolation 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)].

• OSTI ID: 20719643
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Journal Name: Physical Review. B, Condensed Matter and Materials Physics Journal Issue: 16 Vol. 72; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ACTIVATION ENERGY
CURIE POINT
ELECTRIC CONDUCTIVITY
EPITAXY
FERROMAGNETIC MATERIALS
FILMS
GERMANIUM
GERMANIUM COMPOUNDS
HALL EFFECT
HOLES
KERR EFFECT
LAYERS
MAGNETIC PROPERTIES
MAGNETIC SEMICONDUCTORS
MAGNETO-OPTICAL EFFECTS
MANGANESE COMPOUNDS
POLARONS
TEMPERATURE DEPENDENCE