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Direct exchange interaction of localized spins associated with unpaired sp electrons in Be-doped low-temperature-grown GaAs layers

Beryllium-doped GaAs layers grown at low temperatures by molecular-beam epitaxy contain localized spins associated with unpaired sp electrons of As Ga + ions. Interactions of these localized spins are investigated by measuring the magnetization with a superconducting quantum interference device and...

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Main Authors: Bae, K. W., Mohamed, Mohd Ambri, Jung, DaeWon, Otsuka, Nobuo
Format: Article
Language:English
Published: American Institute of Physics 2011
Subjects:
QC Physics
QD Chemistry
TK7885 Computer engineering
Online Access:http://irep.iium.edu.my/29879/1/Direct_exchange_interaction_of_localized_spins_associated_with_unpaired_sp_electrons_in_Be-doped_lT-GaAs.pdf
http://irep.iium.edu.my/29879/
http://jap.aip.org/resource/1/japiau/v109/i7/p073918_s1
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spelling my.iium.irep.298792013-07-25T07:14:51Z http://irep.iium.edu.my/29879/ Direct exchange interaction of localized spins associated with unpaired sp electrons in Be-doped low-temperature-grown GaAs layers Bae, K. W. Mohamed, Mohd Ambri Jung, DaeWon Otsuka, Nobuo QC Physics QD Chemistry TK7885 Computer engineering Beryllium-doped GaAs layers grown at low temperatures by molecular-beam epitaxy contain localized spins associated with unpaired sp electrons of As Ga + ions. Interactions of these localized spins are investigated by measuring the magnetization with a superconducting quantum interference device and the peak-to-peak width of electron paramagnetic resonance (EPR) spectra for samples with different spin concentrations ranging from 3 10 18 to 2.0 10 19cm -3. The results show that localized spins in this material antiferromagnetically interact on each other via direct exchange. From the analysis of the temperature dependence and field dependence of the magnetization on the basis of the Curie-Weiss law and the molecular-field approximation, exchange energy of each sample was derived. The dependence of the exchange energy on the concentration of localized spins is reasonably explained by a model of direct exchange, which results from the overlapping of wave functions of unpaired electrons at As Ga + ions. The peak-to-peak width of EPR spectra increases with an increase in the spin concentration at low temperatures, whereas it decreases with an increase in the temperature for samples with high spin concentrations. These EPR results also show that significant exchange interactions indeed occur between localized spins in this material. These effects of direct exchange interactions between localized spins can clearly be observed at their average distances of around 4 nm, which implies a considerably large spatial extension of the wave function of an unpaired sp electron around an As Ga + ion. American Institute of Physics 2011-04-11 Article REM application/pdf en http://irep.iium.edu.my/29879/1/Direct_exchange_interaction_of_localized_spins_associated_with_unpaired_sp_electrons_in_Be-doped_lT-GaAs.pdf Bae, K. W. and Mohamed, Mohd Ambri and Jung, DaeWon and Otsuka, Nobuo (2011) Direct exchange interaction of localized spins associated with unpaired sp electrons in Be-doped low-temperature-grown GaAs layers. Journal of Applied Physics, 109 (7). ISSN 0021-8979 http://jap.aip.org/resource/1/japiau/v109/i7/p073918_s1 10.1063/1.3567914]
institution Universiti Islam Antarabangsa Malaysia
building IIUM Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider International Islamic University Malaysia
content_source IIUM Repository (IREP)
url_provider http://irep.iium.edu.my/
language English
topic QC Physics
QD Chemistry
TK7885 Computer engineering
spellingShingle QC Physics
QD Chemistry
TK7885 Computer engineering
Bae, K. W.
Mohamed, Mohd Ambri
Jung, DaeWon
Otsuka, Nobuo
Direct exchange interaction of localized spins associated with unpaired sp electrons in Be-doped low-temperature-grown GaAs layers
description Beryllium-doped GaAs layers grown at low temperatures by molecular-beam epitaxy contain localized spins associated with unpaired sp electrons of As Ga + ions. Interactions of these localized spins are investigated by measuring the magnetization with a superconducting quantum interference device and the peak-to-peak width of electron paramagnetic resonance (EPR) spectra for samples with different spin concentrations ranging from 3 10 18 to 2.0 10 19cm -3. The results show that localized spins in this material antiferromagnetically interact on each other via direct exchange. From the analysis of the temperature dependence and field dependence of the magnetization on the basis of the Curie-Weiss law and the molecular-field approximation, exchange energy of each sample was derived. The dependence of the exchange energy on the concentration of localized spins is reasonably explained by a model of direct exchange, which results from the overlapping of wave functions of unpaired electrons at As Ga + ions. The peak-to-peak width of EPR spectra increases with an increase in the spin concentration at low temperatures, whereas it decreases with an increase in the temperature for samples with high spin concentrations. These EPR results also show that significant exchange interactions indeed occur between localized spins in this material. These effects of direct exchange interactions between localized spins can clearly be observed at their average distances of around 4 nm, which implies a considerably large spatial extension of the wave function of an unpaired sp electron around an As Ga + ion.
format Article
author Bae, K. W.
Mohamed, Mohd Ambri
Jung, DaeWon
Otsuka, Nobuo
author_facet Bae, K. W.
Mohamed, Mohd Ambri
Jung, DaeWon
Otsuka, Nobuo
author_sort Bae, K. W.
title Direct exchange interaction of localized spins associated with unpaired sp electrons in Be-doped low-temperature-grown GaAs layers
title_short Direct exchange interaction of localized spins associated with unpaired sp electrons in Be-doped low-temperature-grown GaAs layers
title_full Direct exchange interaction of localized spins associated with unpaired sp electrons in Be-doped low-temperature-grown GaAs layers
title_fullStr Direct exchange interaction of localized spins associated with unpaired sp electrons in Be-doped low-temperature-grown GaAs layers
title_full_unstemmed Direct exchange interaction of localized spins associated with unpaired sp electrons in Be-doped low-temperature-grown GaAs layers
title_sort direct exchange interaction of localized spins associated with unpaired sp electrons in be-doped low-temperature-grown gaas layers
publisher American Institute of Physics
publishDate 2011
url http://irep.iium.edu.my/29879/1/Direct_exchange_interaction_of_localized_spins_associated_with_unpaired_sp_electrons_in_Be-doped_lT-GaAs.pdf
http://irep.iium.edu.my/29879/
http://jap.aip.org/resource/1/japiau/v109/i7/p073918_s1
_version_ 1643609773765033984
score 13.211869

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