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Electronic and magnetic properties of SnO2/CrO2 thin superlattices.

Borges PD, Scolfaro LM, Leite Alves HW, da Silva EF, Assali LV - Nanoscale Res Lett (2011)

Bottom Line: In this article, using first-principles electronic structure calculations within the spin density functional theory, alternated magnetic and non-magnetic layers of rutile-CrO2 and rutile-SnO2 respectively, in a (CrO2)n(SnO2)n superlattice (SL) configuration, with n being the number of monolayers which are considered equal to 1, 2, ..., 10 are studied.A half-metallic behavior is observed for the (CrO2)n(SnO2)n SLs for all values of n.The ground state is found to be FM with a magnetic moment of 2 μB per chromium atom, and this result does not depend on the number of monolayers n.

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Affiliation: Instituto de Física, Universidade de São Paulo, CP 66318, São Paulo, SP, 05315-970, Brazil. pdborges@gmail.com.

ABSTRACT
In this article, using first-principles electronic structure calculations within the spin density functional theory, alternated magnetic and non-magnetic layers of rutile-CrO2 and rutile-SnO2 respectively, in a (CrO2)n(SnO2)n superlattice (SL) configuration, with n being the number of monolayers which are considered equal to 1, 2, ..., 10 are studied. A half-metallic behavior is observed for the (CrO2)n(SnO2)n SLs for all values of n. The ground state is found to be FM with a magnetic moment of 2 μB per chromium atom, and this result does not depend on the number of monolayers n. As the FM rutile-CrO2 is unstable at ambient temperature, and known to be stabilized when on top of SnO2, the authors suggest that (CrO2)n(SnO2)n SLs may be applied to spintronic technologies since they provide efficient spin-polarized carriers.

No MeSH data available.


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Study of strain effects on the magnetic behavior. (a) Total energy versus the c/aSnO2 parameter for bulk rutile-CrO2 for AFM, FM, and NM states. (b) Magnetic moment per cell versus the c/aSnO2 parameter.
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Figure 4: Study of strain effects on the magnetic behavior. (a) Total energy versus the c/aSnO2 parameter for bulk rutile-CrO2 for AFM, FM, and NM states. (b) Magnetic moment per cell versus the c/aSnO2 parameter.

Mentions: An investigation, related to strain effects along the z-direction for the rutile phase of CrO2, was made by simulating bulk rutile-CrO2, on top of tin dioxide, assuming for CrO2 the lattice parameter a of SnO2, i.e., a situation in which the chromium dioxide is tensile. By varying the ratio c/aSnO2 and minimizing the total energy of the system, the authors obtained the curves shown in Figure 4a for the FM, AFM, and NM states, showing that the transition from a FM to an AFM state occurs when c/aSnO2 is about 0.544. At this value, a magnetic moment reduction is observed, as depicted in Figure 4b. These results suggest a magnetization change when the SL is under strain or, in other words, when CrO2 is compressed. A similar behavior was found by Srivastava et al. for bulk rutile-CrO2 under pressure [11].


Electronic and magnetic properties of SnO2/CrO2 thin superlattices.

Borges PD, Scolfaro LM, Leite Alves HW, da Silva EF, Assali LV - Nanoscale Res Lett (2011)

Study of strain effects on the magnetic behavior. (a) Total energy versus the c/aSnO2 parameter for bulk rutile-CrO2 for AFM, FM, and NM states. (b) Magnetic moment per cell versus the c/aSnO2 parameter.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211196&req=5

Figure 4: Study of strain effects on the magnetic behavior. (a) Total energy versus the c/aSnO2 parameter for bulk rutile-CrO2 for AFM, FM, and NM states. (b) Magnetic moment per cell versus the c/aSnO2 parameter.
Mentions: An investigation, related to strain effects along the z-direction for the rutile phase of CrO2, was made by simulating bulk rutile-CrO2, on top of tin dioxide, assuming for CrO2 the lattice parameter a of SnO2, i.e., a situation in which the chromium dioxide is tensile. By varying the ratio c/aSnO2 and minimizing the total energy of the system, the authors obtained the curves shown in Figure 4a for the FM, AFM, and NM states, showing that the transition from a FM to an AFM state occurs when c/aSnO2 is about 0.544. At this value, a magnetic moment reduction is observed, as depicted in Figure 4b. These results suggest a magnetization change when the SL is under strain or, in other words, when CrO2 is compressed. A similar behavior was found by Srivastava et al. for bulk rutile-CrO2 under pressure [11].

Bottom Line: In this article, using first-principles electronic structure calculations within the spin density functional theory, alternated magnetic and non-magnetic layers of rutile-CrO2 and rutile-SnO2 respectively, in a (CrO2)n(SnO2)n superlattice (SL) configuration, with n being the number of monolayers which are considered equal to 1, 2, ..., 10 are studied.A half-metallic behavior is observed for the (CrO2)n(SnO2)n SLs for all values of n.The ground state is found to be FM with a magnetic moment of 2 μB per chromium atom, and this result does not depend on the number of monolayers n.

View Article: PubMed Central - HTML - PubMed

Affiliation: Instituto de Física, Universidade de São Paulo, CP 66318, São Paulo, SP, 05315-970, Brazil. pdborges@gmail.com.

ABSTRACT
In this article, using first-principles electronic structure calculations within the spin density functional theory, alternated magnetic and non-magnetic layers of rutile-CrO2 and rutile-SnO2 respectively, in a (CrO2)n(SnO2)n superlattice (SL) configuration, with n being the number of monolayers which are considered equal to 1, 2, ..., 10 are studied. A half-metallic behavior is observed for the (CrO2)n(SnO2)n SLs for all values of n. The ground state is found to be FM with a magnetic moment of 2 μB per chromium atom, and this result does not depend on the number of monolayers n. As the FM rutile-CrO2 is unstable at ambient temperature, and known to be stabilized when on top of SnO2, the authors suggest that (CrO2)n(SnO2)n SLs may be applied to spintronic technologies since they provide efficient spin-polarized carriers.

No MeSH data available.


Related in: MedlinePlus