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Strain-induced high ferromagnetic transition temperature of MnAs epilayer grown on GaAs (110).

Xu P, Lu J, Chen L, Yan S, Meng H, Pan G, Zhao J - Nanoscale Res Lett (2011)

Bottom Line: Specular and grazing incidence X-ray diffractions are used to study the influence of different strain states of MnAs/GaAs (110) and MnAs/GaAs (001) on the first-order magnetostructural phase transition.It comes out that the first-order magnetostructural phase transition temperature Tt, at which the remnant magnetization becomes zero, is strongly affected by the strain constraint from different oriented GaAs substrates.Our results show an elevated Tt of 350 K for MnAs films grown on GaAs (110) surface, which is attributed to the effect of strain constraint from different directions.PACS: 68.35.Rh, 61.50.Ks, 81.15.Hi, 07.85.Qe.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, P,O, Box 912, Beijing 100083, China. jhzhao@red.semi.ac.cn.

ABSTRACT
MnAs films are grown on GaAs surfaces by molecular beam epitaxy. Specular and grazing incidence X-ray diffractions are used to study the influence of different strain states of MnAs/GaAs (110) and MnAs/GaAs (001) on the first-order magnetostructural phase transition. It comes out that the first-order magnetostructural phase transition temperature Tt, at which the remnant magnetization becomes zero, is strongly affected by the strain constraint from different oriented GaAs substrates. Our results show an elevated Tt of 350 K for MnAs films grown on GaAs (110) surface, which is attributed to the effect of strain constraint from different directions.PACS: 68.35.Rh, 61.50.Ks, 81.15.Hi, 07.85.Qe.

No MeSH data available.


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Temperature dependence and magnetic field dependence of magnetization. a Temperature dependence of the remnant magnetization Mr for samples A-D. Mr remains over zero even when the temperature reaches 340 and 350 K for samples B and D, respectively. b The magnetic field dependence of magnetization for MnAs grown on GaAs (110) and GaAs (001) at 300 K, under a magnetic field applied along the easy axis of magnetization.
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Figure 4: Temperature dependence and magnetic field dependence of magnetization. a Temperature dependence of the remnant magnetization Mr for samples A-D. Mr remains over zero even when the temperature reaches 340 and 350 K for samples B and D, respectively. b The magnetic field dependence of magnetization for MnAs grown on GaAs (110) and GaAs (001) at 300 K, under a magnetic field applied along the easy axis of magnetization.

Mentions: The remnant magnetization Mr as a function of temperature T is plotted in Figure 4a. The linear decrease of Mr at low temperature is caused by thermal fluctuation, while the rapid decreasing at high temperature is caused by structural transition from hexagonal phase to orthorhombic phase. As the thickness can change magnetic property of MnAs epilayer [7,25], Mr becomes zero when the temperature reaches 340 and 350 K for samples B and sample D, respectively. In accordance with RHEED pattern analysis given above, Mr exceeds 1,200 emu/cm3 at 5 K for sample D, which is a bit larger than the saturation magnetization reported for MnAs/GaAs (001) at 10 K with little crystal defect and optimum intra- and inter-stripe magnetic coupling [26]. The remarkable magnetic property difference between sample C and sample D may originate from the different growth conditions, such as the low substrate temperature and over pressure of As4 for sample C, or different stoichiometry. Figure 4b shows M-H hysteresis loops measured at room temperature with magnetic field applied along the direction of MnAs , the easy axis of magnetization. The magnetization hysteresis loops show a perfect square form for all the samples studied here.


Strain-induced high ferromagnetic transition temperature of MnAs epilayer grown on GaAs (110).

Xu P, Lu J, Chen L, Yan S, Meng H, Pan G, Zhao J - Nanoscale Res Lett (2011)

Temperature dependence and magnetic field dependence of magnetization. a Temperature dependence of the remnant magnetization Mr for samples A-D. Mr remains over zero even when the temperature reaches 340 and 350 K for samples B and D, respectively. b The magnetic field dependence of magnetization for MnAs grown on GaAs (110) and GaAs (001) at 300 K, under a magnetic field applied along the easy axis of magnetization.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211171&req=5

Figure 4: Temperature dependence and magnetic field dependence of magnetization. a Temperature dependence of the remnant magnetization Mr for samples A-D. Mr remains over zero even when the temperature reaches 340 and 350 K for samples B and D, respectively. b The magnetic field dependence of magnetization for MnAs grown on GaAs (110) and GaAs (001) at 300 K, under a magnetic field applied along the easy axis of magnetization.
Mentions: The remnant magnetization Mr as a function of temperature T is plotted in Figure 4a. The linear decrease of Mr at low temperature is caused by thermal fluctuation, while the rapid decreasing at high temperature is caused by structural transition from hexagonal phase to orthorhombic phase. As the thickness can change magnetic property of MnAs epilayer [7,25], Mr becomes zero when the temperature reaches 340 and 350 K for samples B and sample D, respectively. In accordance with RHEED pattern analysis given above, Mr exceeds 1,200 emu/cm3 at 5 K for sample D, which is a bit larger than the saturation magnetization reported for MnAs/GaAs (001) at 10 K with little crystal defect and optimum intra- and inter-stripe magnetic coupling [26]. The remarkable magnetic property difference between sample C and sample D may originate from the different growth conditions, such as the low substrate temperature and over pressure of As4 for sample C, or different stoichiometry. Figure 4b shows M-H hysteresis loops measured at room temperature with magnetic field applied along the direction of MnAs , the easy axis of magnetization. The magnetization hysteresis loops show a perfect square form for all the samples studied here.

Bottom Line: Specular and grazing incidence X-ray diffractions are used to study the influence of different strain states of MnAs/GaAs (110) and MnAs/GaAs (001) on the first-order magnetostructural phase transition.It comes out that the first-order magnetostructural phase transition temperature Tt, at which the remnant magnetization becomes zero, is strongly affected by the strain constraint from different oriented GaAs substrates.Our results show an elevated Tt of 350 K for MnAs films grown on GaAs (110) surface, which is attributed to the effect of strain constraint from different directions.PACS: 68.35.Rh, 61.50.Ks, 81.15.Hi, 07.85.Qe.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, P,O, Box 912, Beijing 100083, China. jhzhao@red.semi.ac.cn.

ABSTRACT
MnAs films are grown on GaAs surfaces by molecular beam epitaxy. Specular and grazing incidence X-ray diffractions are used to study the influence of different strain states of MnAs/GaAs (110) and MnAs/GaAs (001) on the first-order magnetostructural phase transition. It comes out that the first-order magnetostructural phase transition temperature Tt, at which the remnant magnetization becomes zero, is strongly affected by the strain constraint from different oriented GaAs substrates. Our results show an elevated Tt of 350 K for MnAs films grown on GaAs (110) surface, which is attributed to the effect of strain constraint from different directions.PACS: 68.35.Rh, 61.50.Ks, 81.15.Hi, 07.85.Qe.

No MeSH data available.


Related in: MedlinePlus