Enhancing the Curie Temperature of Ferromagnetic Semiconductor (Ga,Mn)As to 200 K via Nanostructure Engineering

Chen, Lin; Yang, Xiang; Fu, Yang; Zhao, Jianhua; Misuraca, Jennifer; Xiong, Peng; Molnár, S. von

doi:10.1021/nl201187m

Cited by 295 publications

(183 citation statements)

References 36 publications

(55 reference statements)

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“…The only real use for the modified Arrott plots in this case is therefore as a T C consistency check after the determination of β and γ . Arrott plots of this type have been used to obtain T C values for (Ga,Mn)As samples [37], assuming mean field exponent values without any justification.…”

Section: B Arrott-noakes Plotsmentioning

confidence: 99%

Three-dimensional Heisenberg critical behavior in the highly disordered dilute ferromagnetic semiconductor (Ga,Mn)As

et al. 2016

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We present detailed studies of critical behavior in the strongly site-disordered dilute ferromagnetic semiconductor (Ga,Mn)As. (Ga,Mn)As has a low saturation magnetization and relatively strong magnetocrystalline anisotropy. This combination of properties inhibits domain formation, thus removing a principal experimental difficulty in determining the critical coefficients β and γ . We find that there are still a large number of problems to overcome in terms of measurement procedures and methods of analysis. In particular, the combined effects of disorder and inhomogeneity limit the accessible critical region. However, we find that accurate and reproducible values of the critical exponents β and γ can be obtained from Kouvel-Fisher plots of remanent magnetization and magnetic susceptibility for our (Ga,Mn)As samples. The values of β and γ obtained are consistent with those of the three-dimensional Heisenberg class, despite the very strong disorder present in this system, and they are inconsistent with mean field behavior. Log-log plots of M(H ) data for our samples are consistent with the three-dimensional Heisenberg value of the critical exponent δ, but accurate values of δ could not be obtained for our samples from these plots. We also find that accurate values of the critical exponent α could not be obtained by fitting to the measured temperature derivative of resistivity for our samples. We find that modified Arrott plots and scaling plots are not a practical way to determine the universality class or critical exponents, though they are found to be in better agreement with three-dimensional Heisenberg values than mean field values. Below the critical temperature range, we find that the magnetization shows power-law behavior down to a reduced temperature of t ∼ 0.5, with a critical exponent β ∼ 0.4, a value appreciably lower than the mean field value of β = 0.5. At lower temperatures, Bloch 3/2 law behavior is observed due to magnons.

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Section: B Arrott-noakes Plotsmentioning

confidence: 99%

Three-dimensional Heisenberg critical behavior in the highly disordered dilute ferromagnetic semiconductor (Ga,Mn)As

et al. 2016

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“…4 The highest T C of (Ga,Mn)As up to ∼200 K with ∼12% of Mn doping has been reported. 8,9 However, the (Ga,Mn)As system still faces several serious challenges. For example, substitution of divalent Mn 2+ into trivalent Ga 3+ provides both holes carriers and magnetic atoms.…”

Section: Introductionmentioning

confidence: 99%

Li(Zn,Co,Mn)As: A bulk form diluted magnetic semiconductor with Co and Mn co-doping at Zn sites

Chen

Deng

et al. 2016

AIP Advances

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We report the synthesis and characterization of a series of bulk forms of diluted magnetic semiconductors Li(Zn1-x-yCoxMny)As with a crystal structure close to that of III-V diluted magnetic semiconductor (Ga,Mn)As. No ferromagnetic order occurs with single (Zn,Co) or (Zn, Mn) substitution in the parent compound LiZnAs. Only with co-doped Co and Mn ferromagnetic ordering can occur at the Curie temperature ∼40 K. The maximum saturation moment of the this system reached to 2.17μB/Mn, which is comparable to that of Li (Zn,Mn)As. It is the first time that a diluted magnetic semiconductor with co-doping Co and Mn into Zn sites is achieved in “111” LiZnAs system, which could be utilized to investigate the basic science of ferromagnetism in diluted magnetic semiconductors. In addition, ferromagnetic Li(Zn,Co,Mn)As, antiferromagnetic LiMnAs, and superconducting LiFeAs share square lattice at As layers, which may enable the development of novel heterojunction devices in the future.

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“…Furthermore, as a direct consequence of gate-voltage control of the magnetic anisotropy, it was found that the magnetization direction in (Ga,Mn)As films could also be changed by a gate electric-field, providing an alternative method to the electrical switching of magnetization [21]. The main obstacle for the practical applications of III-V DMS remains the low Curie temperatures, with the record sticking at about 200 K for (Ga,Mn)As nanowires [22]. For this reason, similar schemes were attempted on ultrathin ferromagnetic metal films at room temperature, despite persisting doubts on whether the tiny signal could be observed/exploited [23].…”

Section: Introductionmentioning

confidence: 99%

Control of Magnetism in Dilute Magnetic Semiconductor (Ga,Mn)As Films by Surface Decoration of Molecules

Wang

Xiong

et al. 2016

Front. Phys.

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The responses of magnetic moments to external stimuli such as magnetic-field, heat, light, and electric-field have been utilized to manipulate the magnetism in magnetic semiconductors, with many of the novel ideas applied even to ferromagnetic metals. Here, we review a new experimental development on the control of magnetism in (Ga,Mn)As thin films by surface decoration of organic molecules: Molecules deposited on the surface of (Ga,Mn)As thin films are shown to be capable of significantly modulating their saturation magnetization and Curie temperature. These phenomena are shown to originate from the carrier-mediated ferromagnetism in (Ga,Mn)As and the surface molecules acting as acceptors or donors depending on their highest occupied molecular orbitals, resembling the charge transfer mechanism in a pn junction in which the equilibrium state is reached on the alignment of Fermi levels.

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Enhancing the Curie Temperature of Ferromagnetic Semiconductor (Ga,Mn)As to 200 K via Nanostructure Engineering

Cited by 295 publications

References 36 publications

Three-dimensional Heisenberg critical behavior in the highly disordered dilute ferromagnetic semiconductor (Ga,Mn)As

Three-dimensional Heisenberg critical behavior in the highly disordered dilute ferromagnetic semiconductor (Ga,Mn)As

Li(Zn,Co,Mn)As: A bulk form diluted magnetic semiconductor with Co and Mn co-doping at Zn sites

Control of Magnetism in Dilute Magnetic Semiconductor (Ga,Mn)As Films by Surface Decoration of Molecules

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