Magnetotransport properties of the diluted ferromagnetic semiconductor (Ga,Mn)As

Natalia Lebedeva, S. Novikov, T. Saloniemi, Pekka Kuivalainen

Research output: Contribution to journalArticleScientificpeer-review

Abstract

We have studied experimentally the magnetotransport properties of a p-type diluted ferromagnetic semiconductor Ga1–xMnxAs by measuring the resistivity and Hall-effect as a function of temperature in various magnetic fields. The Ga1–xMnxAs thin films with thickness 1µm were grown on semi-insulating GaAs substrates by using a low temperature molecular beam epitaxy (MBE) technique and varying the Mn concentration between x=0.02 and x=0.05. The samples with x ≤ 0.03 showed insulating behaviour at low temperatures (resistivity ~1/T), whereas the samples with x ≥ 0.04 showed metallic behaviour (a finite resistivity at low temperatures). In the metallic samples the exchange interaction between the hole spins in the valence band and the spins of the Mn 3d electrons was manifested in the anomalous Hall-effect (AHE), from which the ferromagnetic transition temperature TC = 30K was estimated. Further, a resistivity peak appeared at TC in the metallic samples. The AHE can be explained by the wellknown theory for the Hall-effect in ferromagnetic conductors, where the AHE is proportional to the average spin-polarization of the magnetic lattice. The resistivity vs. temperature can be described accurately by a model, where a transport mechanism for disordered heavily doped semiconductors is combined with the spin disorder scattering processes due to the exchange interaction. This model explains both the resistivity peak at TC in the metallic samples and the temperature dependence of the resistivity in the semiconducting samples.
Original languageEnglish
Pages (from-to)85 - 87
Number of pages3
JournalPhysica Scripta
VolumeT114
DOIs
Publication statusPublished - 2004
MoE publication typeA1 Journal article-refereed
Event20th Nordic Semiconductor Meeting, NSM20 - Tampere, Finland
Duration: 25 Aug 200327 Aug 2003

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Resistivity
Gallium Arsenide
Hall Effect
Semiconductors
Hall effect
electrical resistivity
Anomalous
Exchange Interaction
Spin Polarization
Epitaxy
Temperature Dependence
Conductor
Disorder
Thin Films
molecular beam epitaxy
conductors
Directly proportional
Magnetic Field
transition temperature
Substrate

Cite this

Lebedeva, Natalia ; Novikov, S. ; Saloniemi, T. ; Kuivalainen, Pekka. / Magnetotransport properties of the diluted ferromagnetic semiconductor (Ga,Mn)As. In: Physica Scripta. 2004 ; Vol. T114. pp. 85 - 87.
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abstract = "We have studied experimentally the magnetotransport properties of a p-type diluted ferromagnetic semiconductor Ga1–xMnxAs by measuring the resistivity and Hall-effect as a function of temperature in various magnetic fields. The Ga1–xMnxAs thin films with thickness 1µm were grown on semi-insulating GaAs substrates by using a low temperature molecular beam epitaxy (MBE) technique and varying the Mn concentration between x=0.02 and x=0.05. The samples with x ≤ 0.03 showed insulating behaviour at low temperatures (resistivity ~1/T), whereas the samples with x ≥ 0.04 showed metallic behaviour (a finite resistivity at low temperatures). In the metallic samples the exchange interaction between the hole spins in the valence band and the spins of the Mn 3d electrons was manifested in the anomalous Hall-effect (AHE), from which the ferromagnetic transition temperature TC = 30K was estimated. Further, a resistivity peak appeared at TC in the metallic samples. The AHE can be explained by the wellknown theory for the Hall-effect in ferromagnetic conductors, where the AHE is proportional to the average spin-polarization of the magnetic lattice. The resistivity vs. temperature can be described accurately by a model, where a transport mechanism for disordered heavily doped semiconductors is combined with the spin disorder scattering processes due to the exchange interaction. This model explains both the resistivity peak at TC in the metallic samples and the temperature dependence of the resistivity in the semiconducting samples.",
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Magnetotransport properties of the diluted ferromagnetic semiconductor (Ga,Mn)As. / Lebedeva, Natalia; Novikov, S.; Saloniemi, T.; Kuivalainen, Pekka.

In: Physica Scripta, Vol. T114, 2004, p. 85 - 87.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Magnetotransport properties of the diluted ferromagnetic semiconductor (Ga,Mn)As

AU - Lebedeva, Natalia

AU - Novikov, S.

AU - Saloniemi, T.

AU - Kuivalainen, Pekka

PY - 2004

Y1 - 2004

N2 - We have studied experimentally the magnetotransport properties of a p-type diluted ferromagnetic semiconductor Ga1–xMnxAs by measuring the resistivity and Hall-effect as a function of temperature in various magnetic fields. The Ga1–xMnxAs thin films with thickness 1µm were grown on semi-insulating GaAs substrates by using a low temperature molecular beam epitaxy (MBE) technique and varying the Mn concentration between x=0.02 and x=0.05. The samples with x ≤ 0.03 showed insulating behaviour at low temperatures (resistivity ~1/T), whereas the samples with x ≥ 0.04 showed metallic behaviour (a finite resistivity at low temperatures). In the metallic samples the exchange interaction between the hole spins in the valence band and the spins of the Mn 3d electrons was manifested in the anomalous Hall-effect (AHE), from which the ferromagnetic transition temperature TC = 30K was estimated. Further, a resistivity peak appeared at TC in the metallic samples. The AHE can be explained by the wellknown theory for the Hall-effect in ferromagnetic conductors, where the AHE is proportional to the average spin-polarization of the magnetic lattice. The resistivity vs. temperature can be described accurately by a model, where a transport mechanism for disordered heavily doped semiconductors is combined with the spin disorder scattering processes due to the exchange interaction. This model explains both the resistivity peak at TC in the metallic samples and the temperature dependence of the resistivity in the semiconducting samples.

AB - We have studied experimentally the magnetotransport properties of a p-type diluted ferromagnetic semiconductor Ga1–xMnxAs by measuring the resistivity and Hall-effect as a function of temperature in various magnetic fields. The Ga1–xMnxAs thin films with thickness 1µm were grown on semi-insulating GaAs substrates by using a low temperature molecular beam epitaxy (MBE) technique and varying the Mn concentration between x=0.02 and x=0.05. The samples with x ≤ 0.03 showed insulating behaviour at low temperatures (resistivity ~1/T), whereas the samples with x ≥ 0.04 showed metallic behaviour (a finite resistivity at low temperatures). In the metallic samples the exchange interaction between the hole spins in the valence band and the spins of the Mn 3d electrons was manifested in the anomalous Hall-effect (AHE), from which the ferromagnetic transition temperature TC = 30K was estimated. Further, a resistivity peak appeared at TC in the metallic samples. The AHE can be explained by the wellknown theory for the Hall-effect in ferromagnetic conductors, where the AHE is proportional to the average spin-polarization of the magnetic lattice. The resistivity vs. temperature can be described accurately by a model, where a transport mechanism for disordered heavily doped semiconductors is combined with the spin disorder scattering processes due to the exchange interaction. This model explains both the resistivity peak at TC in the metallic samples and the temperature dependence of the resistivity in the semiconducting samples.

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DO - 10.1088/0031-8949/2004/T114/020

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VL - T114

SP - 85

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JO - Physica Scripta

JF - Physica Scripta

SN - 0031-8949

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