Modeling spin Hamiltonian parameters for Fe2+ adatoms on Cu2N/Cu(1 0 0) surface: Semiempirical microscopic spin Hamiltonian approach

Rudowicz, Czesław; Tadyszak, Krzysztof; Ślusarski, Tomasz

doi:10.1016/j.jmmm.2019.04.099

Cited by 4 publications

(2 citation statements)

References 64 publications

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“…For example, M (T, B) characteristic of a single substitutional transition metal ion in a given semiconductor can be obtained using the full quantummechanical crystal field model approach. The CFM was developed by Vallin [14,15] for II-VI dilute magnetic semiconductors doped with Cr, and then successfully applied for other DMSs [9,[16][17][18][19][20][21][22][23]. Recently it was shown that CFM simulations can explain magnetic [9,21,22], magnetooptic [19] and even magnetoelectric [10] properties in dilute Ga 1−x Mn x N, with x ≤ 0.03.…”

Section: Modelmentioning

confidence: 99%

Crystal field model simulations of magnetic response of pairs, triplets and quartets of Mn³⁺ ions in GaN

et al. 2020

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A ferromagnetic coupling between localized Mn spins was predicted in a series of ab initio and tight binding calculations and experimentally verified for the dilute magnetic semiconductor Ga1−x Mn x N. In the limit of small Mn concentrations, x ≲ 0.01, the paramagnetic properties of this material were successfully described using a single ion crystal field model approach. In order to obtain the description of magnetization in (Ga,Mn)N in the presence of interacting magnetic centers, we extend the previous model of a single substitutional Mn3+ ion in GaN by considering pairs, triplets and quartets of Mn3+ ions coupled by a ferromagnetic superexchange interaction. Using this approach we investigate how the magnetic properties, particularly the magnitude of the uniaxial anisotropy field, change as the number of magnetic Mn3+ ions in a given cluster increases from 1 to 4. Our simulations are then exploited in explaining experimental magnetic properties of Ga1−x Mn x N with x ≅ 0.03, where the presence of small magnetic clusters gains in significance. As a result the approximate lower and upper limits for the values of exchange couplings between Mn3+ ions in GaN, being in nearest neighbors (nns) J nn and next nns J nnn positions, respectively, are established.

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Section: Modelmentioning

confidence: 99%

Crystal field model simulations of magnetic response of pairs, triplets and quartets of Mn³⁺ ions in GaN

et al. 2020

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“…Having established the dominant Mn oxidation state in our layers, the Mn concentration can be determined using the crystal field model (CFM) relevant for Mn 3+ [34,37,38,[54][55][56][57][58][59]. The direct CFM computations for noninteracting Mn 3+ cations yield that the near-saturation value at 70 kOe and 2 K is 3.78 µ B per Mn ion [34,36,37].…”

Section: Magnetic Measurements and Discussionmentioning

confidence: 99%

Improved-Sensitivity Integral SQUID Magnetometry of (Ga,Mn)N Thin Films in Proximity to Mg-doped GaN

Gas,

Kunert,

Dluzewski

et al. 2021

Preprint

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Nominally 45 nm GaN:Mg / 5 nm (Ga,Mn)N / 45 nm GaN:Mg trilayers structures prepared by molecular beam epitaxy on GaN-buffered Al2O3 substrates are investigated to verify whether the indirect co-doping by holes from the cladding layers can alter the spin-spin interaction in (Ga,Mn)N. The four investigated structures, differing with the Mg doping level, are carefully characterized at the nanoscale by high-resolution transition electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy, and by secondary ion mass spectrometry. Importantly, HRTEM decisively excluded a presence of foreign Mn-rich phases. The structures, up to medium Mg doping, show no Mg overdoping effects. Magnetic studies of these structures are aided by the employment of a dedicated experimental approach of the in situ compensation of the magnetic contribution from the substrate, allowing up to about fifty-fold reduction of this contribution. This technique, dedicated to these structures, simultaneously provides a tenfold reduction of temporal instabilities of the magnetometric unit and lowers the experimental jitter to merely 5 × 10 −7 emu at 70 kOe, vastly increasing the precision and the credibility of the results of the standard integral superconducting quantum interference device (SQUID) magnetometry in high magnetic fields. The magnetic characteristics of the trilayers structures established here prove identical with the already known properties of the thick (Ga,Mn)N single layers, namely (i) the low temperature ferromagnetism among Mn 3+ ions driven by superexchange and (ii) purely paramagnetic response at higher temperatures. The possible cause of the lack of any effects brought about by the adjacent Mg-doping is a presence of residual Mn in the cladding layers, resulting in the deactivation of the p-type doping intended there. This finding points out that a more intensive technological effort has to be exerted to promote the co-doping-driven carrier-mediated ferromagnetic coupling in Mn-enriched GaN, especially at elevated temperatures.

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Improved-sensitivity integral SQUID magnetometry of (Ga,Mn)N thin films in proximity to Mg-doped GaN

Gas

Kunert

Dłuźewski

et al. 2021

Journal of Alloys and Compounds

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Modeling spin Hamiltonian parameters for Fe2+ adatoms on Cu2N/Cu(1 0 0) surface: Semiempirical microscopic spin Hamiltonian approach

Cited by 4 publications

References 64 publications

Crystal field model simulations of magnetic response of pairs, triplets and quartets of Mn³⁺ ions in GaN

Crystal field model simulations of magnetic response of pairs, triplets and quartets of Mn³⁺ ions in GaN

Improved-Sensitivity Integral SQUID Magnetometry of (Ga,Mn)N Thin Films in Proximity to Mg-doped GaN

Improved-sensitivity integral SQUID magnetometry of (Ga,Mn)N thin films in proximity to Mg-doped GaN

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Modeling spin Hamiltonian parameters for Fe2+ adatoms on Cu2N/Cu(1 0 0) surface: Semiempirical microscopic spin Hamiltonian approach

Cited by 4 publications

References 64 publications

Crystal field model simulations of magnetic response of pairs, triplets and quartets of Mn3+ ions in GaN

Crystal field model simulations of magnetic response of pairs, triplets and quartets of Mn3+ ions in GaN

Improved-Sensitivity Integral SQUID Magnetometry of (Ga,Mn)N Thin Films in Proximity to Mg-doped GaN

Improved-sensitivity integral SQUID magnetometry of (Ga,Mn)N thin films in proximity to Mg-doped GaN

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Product

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Crystal field model simulations of magnetic response of pairs, triplets and quartets of Mn³⁺ ions in GaN

Crystal field model simulations of magnetic response of pairs, triplets and quartets of Mn³⁺ ions in GaN