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NMR spectroscopy for thin films by magnetic resonance force microscopy.

Won S, Saun SB, Lee S, Lee S, Kim K, Han Y - Sci Rep (2013)

Bottom Line: Nuclear magnetic resonance (NMR) is a fundamental research tool that is widely used in many fields.To minimize the amount of imaging information inevitably mixed into the signal when a gradient field is used, we adopted a large magnet with a flat end with a diameter of 336 μm that generates a homogeneous field on the sample plane and a field gradient in a direction perpendicular to the plane.Cyclic adiabatic inversion was used in conjunction with periodic phase inversion of the frequency shift to maximize the SNR.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea [2] Advanced Metallic Materials Division, Korea Institute of Materials Science, Changwon 642-831, Republic of Korea [3].

ABSTRACT
Nuclear magnetic resonance (NMR) is a fundamental research tool that is widely used in many fields. Despite its powerful applications, unfortunately the low sensitivity of conventional NMR makes it difficult to study thin film or nano-sized samples. In this work, we report the first NMR spectrum obtained from general thin films by using magnetic resonance force microscopy (MRFM). To minimize the amount of imaging information inevitably mixed into the signal when a gradient field is used, we adopted a large magnet with a flat end with a diameter of 336 μm that generates a homogeneous field on the sample plane and a field gradient in a direction perpendicular to the plane. Cyclic adiabatic inversion was used in conjunction with periodic phase inversion of the frequency shift to maximize the SNR. In this way, we obtained the (19)F NMR spectrum for a 34 nm-thick CaF2 thin film.

No MeSH data available.


Related in: MedlinePlus

(a), Schematic drawing of the MRFM setup, and (b), CaF2 deposited onto a cantilever. Cantilevers with a length of 450 μm were covered by slide glasses so that only 40 μm at the end undergoes the deposition. The area that appears somewhat dark in the image is where CaF2 is deposited. The black square at the end is the original cantilever tip.
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f1: (a), Schematic drawing of the MRFM setup, and (b), CaF2 deposited onto a cantilever. Cantilevers with a length of 450 μm were covered by slide glasses so that only 40 μm at the end undergoes the deposition. The area that appears somewhat dark in the image is where CaF2 is deposited. The black square at the end is the original cantilever tip.

Mentions: The scheme of our MRFM probe is illustrated in Fig. 1a. Magnetic field B(r) generated by a magnet and a superconducting coil produces magnetization M on the sample. If the frequency of the RF electromagnetic wave generated by a coil, ω, satisfies the resonance condition B(r) = ω/γ, where γ is the gyromagnetic ratio, the magnetization of the sample at that position changes. Then, the force experienced by the sample on the cantilever, F = (M·∇)B(r), also changes. This force change is detected by a fiber-optic interferometer which is used here to measure the cantilever deflection. Samples are 34 ± 2 and 130 ± 5 nm-thick CaF2 thin films deposited directly onto a cantilever by e-beam evaporation (Fig. 1b).


NMR spectroscopy for thin films by magnetic resonance force microscopy.

Won S, Saun SB, Lee S, Lee S, Kim K, Han Y - Sci Rep (2013)

(a), Schematic drawing of the MRFM setup, and (b), CaF2 deposited onto a cantilever. Cantilevers with a length of 450 μm were covered by slide glasses so that only 40 μm at the end undergoes the deposition. The area that appears somewhat dark in the image is where CaF2 is deposited. The black square at the end is the original cantilever tip.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3824162&req=5

f1: (a), Schematic drawing of the MRFM setup, and (b), CaF2 deposited onto a cantilever. Cantilevers with a length of 450 μm were covered by slide glasses so that only 40 μm at the end undergoes the deposition. The area that appears somewhat dark in the image is where CaF2 is deposited. The black square at the end is the original cantilever tip.
Mentions: The scheme of our MRFM probe is illustrated in Fig. 1a. Magnetic field B(r) generated by a magnet and a superconducting coil produces magnetization M on the sample. If the frequency of the RF electromagnetic wave generated by a coil, ω, satisfies the resonance condition B(r) = ω/γ, where γ is the gyromagnetic ratio, the magnetization of the sample at that position changes. Then, the force experienced by the sample on the cantilever, F = (M·∇)B(r), also changes. This force change is detected by a fiber-optic interferometer which is used here to measure the cantilever deflection. Samples are 34 ± 2 and 130 ± 5 nm-thick CaF2 thin films deposited directly onto a cantilever by e-beam evaporation (Fig. 1b).

Bottom Line: Nuclear magnetic resonance (NMR) is a fundamental research tool that is widely used in many fields.To minimize the amount of imaging information inevitably mixed into the signal when a gradient field is used, we adopted a large magnet with a flat end with a diameter of 336 μm that generates a homogeneous field on the sample plane and a field gradient in a direction perpendicular to the plane.Cyclic adiabatic inversion was used in conjunction with periodic phase inversion of the frequency shift to maximize the SNR.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea [2] Advanced Metallic Materials Division, Korea Institute of Materials Science, Changwon 642-831, Republic of Korea [3].

ABSTRACT
Nuclear magnetic resonance (NMR) is a fundamental research tool that is widely used in many fields. Despite its powerful applications, unfortunately the low sensitivity of conventional NMR makes it difficult to study thin film or nano-sized samples. In this work, we report the first NMR spectrum obtained from general thin films by using magnetic resonance force microscopy (MRFM). To minimize the amount of imaging information inevitably mixed into the signal when a gradient field is used, we adopted a large magnet with a flat end with a diameter of 336 μm that generates a homogeneous field on the sample plane and a field gradient in a direction perpendicular to the plane. Cyclic adiabatic inversion was used in conjunction with periodic phase inversion of the frequency shift to maximize the SNR. In this way, we obtained the (19)F NMR spectrum for a 34 nm-thick CaF2 thin film.

No MeSH data available.


Related in: MedlinePlus