Transmission electron microscopy study on ferromagnetic (Ga,Mn)N epitaxial films

Chang, Jee Ho; Kim, G. H.; Lee, J. M.; Han, Sung Hee; Kim, H. J.; Lee, W. Y.; Ham, Moon Ho; Huh, Kwang Soo; Myoung, Jae Min

doi:10.1063/1.1556248

Cited by 23 publications

(8 citation statements)

References 12 publications

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“…The lattice constant decreases with the increase of Mn implantation dose and reaches the smallest at Mn implantation dose of 5 × 10 16 cm −2 , corresponding to 5% Mn concentration. Similar results were also reported by Thaler et al [19], Dhar et al [20] and Chang et al [21]. They considered that the decrease of the lattice constants is due to incorporation of Mn substitutionally on the Ga sites.…”

supporting

confidence: 85%

Study on the Raman scattering measurements of Mn ion implanted GaN

Zhang¹,

Guo²,

Shen³

2006

Materials Science and Engineering: B

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supporting

confidence: 85%

Study on the Raman scattering measurements of Mn ion implanted GaN

Zhang¹,

Guo²,

Shen³

2006

Materials Science and Engineering: B

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“…The mean-field theory predictions, therefore, are believed to have the correct order of magnitude but appear to overestimate the Curie temperature. In previous work [5,6], the Curie temperature estimated by the mean field theory increases with increasing Mn concentration in (Ga,Mn)N films with x = 0.06-0.5%.…”

Section: Resultsmentioning

confidence: 92%

“…Hysteresis loops were measured at temperatures ranging from 4 -300 K using a superconducting quantum interference device (SQUID) magnetometer. In the present work, the Mn concentration was estimated from calculations using the total magnetic moment, provided each Mn atom has the theoretical magnetic moment of 3 µ B [5,6]. Figure 1 shows magnetization versus magnetic field (M-H) curves of the (Ga,Mn)N film with Mn = 0.3% at 5 K and 300 K measured using a SQUID magnetometer with magnetic fields up to 5000 Oe applied parallel to the plane of the films.…”

Section: Methodsmentioning

confidence: 99%

Curie temperature of ferromagnetic (Ga,Mn)N epitaxial films

Lee¹,

Ham²,

Myoung³

et al. 2004

Physica Status Solidi (b)

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PACS 75.47.Pq, 75.50.Pp, 81.15.Hi Electron-mediated ferromagnetism persisting to room temperature has been investigated in epitaxial (Ga,Mn)N films with low Mn concentration grown by plasma-enhanced molecular beam epitaxy (PEMBE).The experimental value of T C (~325 K) in the (Ga,Mn)N film with x = 0.3% from the difference (∆M) between field-cooled (FC) and zero field-cooled (ZFC) magnetization curves is found to be lower than the estimated value of T C (~407 K), obtained by the mean field approximations. The extra-ordinary Hall effect in the epitaxial (Ga,Mn)N film with x = 0.2% is found to appear in the temperature range 100 K -300 K. [1] predicted on the basis of the mean-field Zener model of ferromagnetism that the Curie temperature (T C ) for GaN and ZnO can be higher than room temperature, wide bandgap semiconductors are of central importance in the search for novel diluted magnetic semiconductors (DMSs). In particular, the recent discovery of ferromagnetic ordering in Mn-doped GaN semiconductors with T C exceeding room temperature has generated intense interest in spintronics for device applications [2 -6]. Although the Curie temperature in the GaMnN system has been estimated by mean field theoretical considerations, the empirical determination of the Curie temperature still remains controversial [2 -6].In this article, we report on electron-induced ferromagnetism persisting to above room temperature in epitaxial (Ga,Mn)N films grown by plasma-enhanced molecular beam epitaxy (PEMBE). We find that T C in the (Ga,Mn)N film with x = 0.3% was estimated to be ∼407 K by fitting the M-T curve with theoretical equations based on the mean field theory. However, the experimental value of T C was observed to be ∼325 K from the temperature dependence of the magnetization difference ∆M = (M FC -M ZFC ) between field-cooled (FC) and zero field-cooled (ZFC) magnetization curves. We discuss the implication of the mean field approximations and experimental results on the Curie temperature in detail.

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“…Another aspect to be taken into account is that spin electronics requires control over the spin direction of the charge carriers injected into devices, which may be facilitated by the ability of the nitrides to change easily from a low-spin state to a high-spin state under the action of an applied magnetic field. Most of the Ga 1Àx Mn x N experimental work to date has been carried out on wurtzite materials [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33]; onlya few recent studies are dedicated to the cubic (ZB) structure [36,37], which may present very different physical and electronic properties [38]. Wurtzite Ga 1Àx Mn x N has been grown in several microcrystalline (x ¼ 0:005) [16], bulk (x ¼ 0:03) [17], epitaxial (x ¼ 0:002-0.14) [18][19][20][21][22][23][24][25][26][27][28][29][30], Mn-implanted (x ¼ 0:1) [31][32][33] and Mn-doped (x ¼ 0:03-0.05) [34,35] forms.…”

Section: Introductionmentioning

confidence: 99%