Upper bound for the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>s</mml:mi><mml:mtext>−</mml:mtext><mml:mi>d</mml:mi></mml:mrow></mml:math>exchange integral in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>n</mml:mi></mml:math>-(Ga,Mn)N:Si from magnetotransport studies

Adhikari, R.; Stefanowicz, W.; Faina, B.; Capuzzo, Giulia; Sawicki, M.; Dietl, T.; Bonanni, A.

doi:10.1103/physrevb.91.205204

Cited by 10 publications

(6 citation statements)

References 43 publications

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“…The main feature provided by this plot is that  LO decreases with x, a fact anticipated on the account of the increase of the c lattice parameter on x in (Ga,Mn)N epilayers [5][23]. This assumption is fully corroborated by the insulating character of magnetically homogeneous (Ga,Mn)N bulk crystals [47] and epilayers [28,[48][49][50], thus no influence of phonon-plasmon coupling is expected here. Now, guided by the spread of the points in Fig.…”

Section: Resultssupporting

confidence: 63%

Raman scattering studies of the lateral Mn distribution in MBE-grown Ga1-Mn N epilayers

Gas

Hommel

Sawicki

2020

Journal of Alloys and Compounds

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Recent interest in very thin single phase Ga 1-x Mn x N dilute magnetic layers increased needs for precise, non-destructive, and relatively fast characterization methods with key issues being the macroscopic lateral Mn distribution and the absolute values of Mn concentration x. We report on resonantly enhanced UV Raman scattering studies of high quality Ga 1−x Mn x N layers grown on GaN templated sapphire by molecular beam epitaxy with 4 < x < 9%. The main advantage of the UV excitation is the restriction of the light penetration depth to nearly a hundred nanometers, eliminating signal from the GaN buffer. Under this conditions we determine the dependence of the 1LO phonon frequency on x, what allows for a fine mapping of its lateral distribution over the entire surface of the samples. Our Raman scanning clearly confirms substantial lateral distribution of Mn atoms across the layer, which is radial with respect to its center. From the established distributions in two deliberately chosen layers the magnitude of the optimal growth temperature for most efficient Mn atoms incorporation in epitaxial GaN has been confirmed. It is shown that the combination of the 1LO line width and its energy provides assessment of the crystalline quality of the investigated layers.

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Section: Resultssupporting

confidence: 63%

Raman scattering studies of the lateral Mn distribution in MBE-grown Ga1-Mn N epilayers

Gas

Hommel

Sawicki

2020

Journal of Alloys and Compounds

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“…As established previously atomic layer deposition (ALD) deposited Al 2 O 3 , as well as HfO 2 , makes excellent insulating layers on GaN, withstanding up to at least 3 MV/cm at 77 K [49][50]. This simple and very effective solution allowed to demonstrate the existence and to quantify the effectiveness of the piezoelectro-magnetic coupling in (Ga,Mn)N [17], and confirmed its outstanding insulating properties [13][14][15] [16], which constitute the functional basis of our device.…”

Section: Methodsmentioning

confidence: 98%

“…This magnetic form of GaN, in which a small percentage of Ga atoms is randomly substituted by Mn, belongs to increasingly important group of Rashba materials [3]. The established strong mid-gap Fermi-level pinning [11] [12] and the absence of a depletion layer, in combination with its insulating character [13] [14][15] [16] and a sizable dielectric strength of at least 5 MV/cm [17], points at Mn containing GaN as a worthwhile insulating buffer material for applications in (high power) nitride devices. By the same token this ferromagnetic insulator appears to be an ideal building block for nitride based spin harnessing concepts, which could further stimulate the development of all-nitride low power information processing and wireless communication technologies based on spin waves, the so called magnonics [18].…”

Section: Introductionmentioning

confidence: 99%

Electrical characteristics of vertical-geometry Schottky junction to magnetic insulator (Ga,Mn)N heteroepitaxially grown on sapphire

Kalbarczyk

Dybko

Gas

et al. 2019

Journal of Alloys and Compounds

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Schottky barrier height and the ideality factor  are established for the first time in the single phase (Ga,Mn)N using a vertical geometry device. The material has been heteroepitaxially grown on commercially available low threading dislocation density GaN:Si template. The observed above 10 M resistances already at room temperature are indicative that a nearly conductive-dislocation-free electrical properties are achieved. The analysis of temperature dependence of the forward bias I-V characteristics in the frame of the thermionic emission model yields Ti-(Ga,Mn)N Schottky barrier height to be slightly lower but close in character to other metal/GaN junctions. However, the large magnitudes of the ideality factor  > 1.5 for T  300 K, point to a sizable current blocking in the structure. While it remains to be seen whether it is due to the presence of (Ga,Mn)N barrier or due to other factors which reduce the effective area of the junction, an existence of a substantial serial resistance may hold the key to explain similar observations in other devices of a corresponding structure and technological relevance.

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“…4(b). The negative ∆σ of Sn 0.97 Mn 0.03 Te is enhanced by the applied µ 0 H. The positive ∆σ in degenerate conductors or alloys with magnetic impurities is attributed to weak localization (WL) [79,80], an orbital mechanism weakening by increasing the applied field, and due to quantum corrections to the conductivity. None of these trends is observed in the case of Sn 0.97 Mn 0.03 Te, where a monotonic increase in the values of negative ∆σ has been observed.…”

Section: A Longitudinal Resistivity and Magnetoconductancementioning

confidence: 97%

Ferromagnetic phase transition in topological crystalline insulator thin films: Interplay of anomalous Hall angle and magnetic anisotropy

et al. 2019

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In magnetic topological phases of matter, the quantum anomalous Hall (QAH) effect is an emergent phenomenon driven by ferromagnetic doping, magnetic proximity effects and strain engineering. The realization of QAH states with multiple dissipationless edge and surface conduction channels defined by a Chern number C ≥ 1 was foreseen for the ferromagnetically ordered SnTe class of topological crystalline insulators (TCIs). From magnetotransport measurements on Sn1−xMnxTe (0.00 ≤ x ≤ 0.08)(111) epitaxial thin films grown by molecular beam epitaxy on BaF2 substrates, hole mediated ferromagnetism is observed in samples with x ≥ 0.06 and the highest Tc ∼ 7.5 K is inferred from an anomalous Hall behavior in Sn0.92Mn0.08Te. The sizable anomalous Hall angle ∼0.3 obtained for Sn0.92Mn0.08Te is one of the greatest reported for magnetic topological materials. The ferromagnetic ordering with perpendicular magnetic anisotropy, complemented by the inception of anomalous Hall effect in the Sn1−xMnxTe layers for a thickness commensurate with the decay length of the top and bottom surface states, points at Sn1−xMnxTe as a preferential platform for the realization of QAH states in ferromagnetic TCIs. arXiv:1907.05716v1 [cond-mat.mes-hall]

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Upper bound for thes−dexchange integral inn-(Ga,Mn)N:Si from magnetotransport studies

Cited by 10 publications

References 43 publications

Raman scattering studies of the lateral Mn distribution in MBE-grown Ga1-Mn N epilayers

Raman scattering studies of the lateral Mn distribution in MBE-grown Ga1-Mn N epilayers

Electrical characteristics of vertical-geometry Schottky junction to magnetic insulator (Ga,Mn)N heteroepitaxially grown on sapphire

Ferromagnetic phase transition in topological crystalline insulator thin films: Interplay of anomalous Hall angle and magnetic anisotropy

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