Limits...
Remote control of magnetostriction-based nanocontacts at room temperature.

Jammalamadaka SN, Kuntz S, Berg O, Kittler W, Kannan UM, Chelvane JA, Sürgers C - Sci Rep (2015)

Bottom Line: This can be achieved by exploiting the magnetostriction effects of ferromagnetic materials.Investigating the conductance in the regime of electron tunneling by mechanical or magnetostrictive control of the electrode separation enables an estimation of the magnetostriction.The present results pave the way to utilize the material in devices based on nano-electromechanical systems operating at room temperature.

View Article: PubMed Central - PubMed

Affiliation: Magnetic Materials and Device Physics Laboratory, Department of Physics, Indian Institute of Technology Hyderabad, Hyderabad 502 205, India.

ABSTRACT
The remote control of the electrical conductance through nanosized junctions at room temperature will play an important role in future nano-electromechanical systems and electronic devices. This can be achieved by exploiting the magnetostriction effects of ferromagnetic materials. Here we report on the electrical conductance of magnetic nanocontacts obtained from wires of the giant magnetostrictive compound Tb0.3Dy0.7Fe1.95 as an active element in a mechanically controlled break-junction device. The nanocontacts are reproducibly switched at room temperature between "open" (zero conductance) and "closed" (nonzero conductance) states by variation of a magnetic field applied perpendicularly to the long wire axis. Conductance measurements in a magnetic field oriented parallel to the long wire axis exhibit a different behaviour where the conductance switches between both states only in a limited field range close to the coercive field. Investigating the conductance in the regime of electron tunneling by mechanical or magnetostrictive control of the electrode separation enables an estimation of the magnetostriction. The present results pave the way to utilize the material in devices based on nano-electromechanical systems operating at room temperature.

No MeSH data available.


Related in: MedlinePlus

Conductance switching of Tb0.3Dy0.7Fe1.95 at low temperatures in different field orientations.(a) Conductance G/G0 in perpendicular field Hy at T = 4.2 K. (b) Conductance G/G0 in parallel field Hx at T = 4.2 K. (c) Magnetization loops obtained at T = 10 K. (d) Qualitative behaviour of the magnetostrictive strains λx and λy calculated from  in Hx and Hy (solid lines), see text for details. In perpendicular field Hy, the strain along the long wire axis is λx = −λy/2 (dashed line). Cartoons visualize the contact configuration in magnetic field due to magnetostriction.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4555029&req=5

f5: Conductance switching of Tb0.3Dy0.7Fe1.95 at low temperatures in different field orientations.(a) Conductance G/G0 in perpendicular field Hy at T = 4.2 K. (b) Conductance G/G0 in parallel field Hx at T = 4.2 K. (c) Magnetization loops obtained at T = 10 K. (d) Qualitative behaviour of the magnetostrictive strains λx and λy calculated from in Hx and Hy (solid lines), see text for details. In perpendicular field Hy, the strain along the long wire axis is λx = −λy/2 (dashed line). Cartoons visualize the contact configuration in magnetic field due to magnetostriction.

Mentions: We now focus on the conductance switching performed at constant temperature T = 4.2 K for different orientations of the magnetic field to explore the effect of magnetic anisotropy on the switching behaviour. The magnetic field could be rotated in the x-y plane of the sample either parallel (x) or perpendicular (y) to the long wire axis. In nanocontact devices, a hysteresis of M(H) can cause negative magnetostrain, which would eventually alter the magnetostriction behaviour λ(H)12. To avoid such effects, we demagnetized the contact before we started the field sweep. Figure 5(a) shows a measurement performed at T = 4.2 K with the magnetic field Hy oriented perpendicularly to the long wire axis (y direction). In this configuration, the device was in the “closed” state before application of the magnetic field. With increasing field Hy the conductance drops at a magnetic field of 0.4–0.5 T and the contact opens due to the extension of the wire diameter along the field (y direction) and the corresponding shrinkage along the wire axis (x direction) due to magnetostriction. In addition, we observe a hysteresis in the switching at negative field due to a hysteresis in the magnetization curve shown in Fig. 5(c) with a coercivity μ0Hc = 0.12 T. For this sample a corresponding hysteresis at positive fields is missing. One reason for this asymmetric behaviour might be the different magnetic domain configurations when the magnetic field is rotated by 180°. We calculate the field dependence of the magnetostrictive strain from the magnetization curve M(Hy) of Fig. 5(c) in both directions as mentioned above, see Fig. 5(d) (blue curves). The behaviour of the magnetostrictive strain λx(Hy)/λxs along the long wire axis x (dashed line) resembles the behaviour of G(Hy). The smooth variation of the magnetostrain with increasing field towards negative values along the x direction gives rise to an increasing separation between the two electrodes until the contact opens. The closing of the contact around zero field is in agreement with the M2(Hy) behaviour, see Fig. 5(d) (dashed curve).


Remote control of magnetostriction-based nanocontacts at room temperature.

Jammalamadaka SN, Kuntz S, Berg O, Kittler W, Kannan UM, Chelvane JA, Sürgers C - Sci Rep (2015)

Conductance switching of Tb0.3Dy0.7Fe1.95 at low temperatures in different field orientations.(a) Conductance G/G0 in perpendicular field Hy at T = 4.2 K. (b) Conductance G/G0 in parallel field Hx at T = 4.2 K. (c) Magnetization loops obtained at T = 10 K. (d) Qualitative behaviour of the magnetostrictive strains λx and λy calculated from  in Hx and Hy (solid lines), see text for details. In perpendicular field Hy, the strain along the long wire axis is λx = −λy/2 (dashed line). Cartoons visualize the contact configuration in magnetic field due to magnetostriction.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4555029&req=5

f5: Conductance switching of Tb0.3Dy0.7Fe1.95 at low temperatures in different field orientations.(a) Conductance G/G0 in perpendicular field Hy at T = 4.2 K. (b) Conductance G/G0 in parallel field Hx at T = 4.2 K. (c) Magnetization loops obtained at T = 10 K. (d) Qualitative behaviour of the magnetostrictive strains λx and λy calculated from in Hx and Hy (solid lines), see text for details. In perpendicular field Hy, the strain along the long wire axis is λx = −λy/2 (dashed line). Cartoons visualize the contact configuration in magnetic field due to magnetostriction.
Mentions: We now focus on the conductance switching performed at constant temperature T = 4.2 K for different orientations of the magnetic field to explore the effect of magnetic anisotropy on the switching behaviour. The magnetic field could be rotated in the x-y plane of the sample either parallel (x) or perpendicular (y) to the long wire axis. In nanocontact devices, a hysteresis of M(H) can cause negative magnetostrain, which would eventually alter the magnetostriction behaviour λ(H)12. To avoid such effects, we demagnetized the contact before we started the field sweep. Figure 5(a) shows a measurement performed at T = 4.2 K with the magnetic field Hy oriented perpendicularly to the long wire axis (y direction). In this configuration, the device was in the “closed” state before application of the magnetic field. With increasing field Hy the conductance drops at a magnetic field of 0.4–0.5 T and the contact opens due to the extension of the wire diameter along the field (y direction) and the corresponding shrinkage along the wire axis (x direction) due to magnetostriction. In addition, we observe a hysteresis in the switching at negative field due to a hysteresis in the magnetization curve shown in Fig. 5(c) with a coercivity μ0Hc = 0.12 T. For this sample a corresponding hysteresis at positive fields is missing. One reason for this asymmetric behaviour might be the different magnetic domain configurations when the magnetic field is rotated by 180°. We calculate the field dependence of the magnetostrictive strain from the magnetization curve M(Hy) of Fig. 5(c) in both directions as mentioned above, see Fig. 5(d) (blue curves). The behaviour of the magnetostrictive strain λx(Hy)/λxs along the long wire axis x (dashed line) resembles the behaviour of G(Hy). The smooth variation of the magnetostrain with increasing field towards negative values along the x direction gives rise to an increasing separation between the two electrodes until the contact opens. The closing of the contact around zero field is in agreement with the M2(Hy) behaviour, see Fig. 5(d) (dashed curve).

Bottom Line: This can be achieved by exploiting the magnetostriction effects of ferromagnetic materials.Investigating the conductance in the regime of electron tunneling by mechanical or magnetostrictive control of the electrode separation enables an estimation of the magnetostriction.The present results pave the way to utilize the material in devices based on nano-electromechanical systems operating at room temperature.

View Article: PubMed Central - PubMed

Affiliation: Magnetic Materials and Device Physics Laboratory, Department of Physics, Indian Institute of Technology Hyderabad, Hyderabad 502 205, India.

ABSTRACT
The remote control of the electrical conductance through nanosized junctions at room temperature will play an important role in future nano-electromechanical systems and electronic devices. This can be achieved by exploiting the magnetostriction effects of ferromagnetic materials. Here we report on the electrical conductance of magnetic nanocontacts obtained from wires of the giant magnetostrictive compound Tb0.3Dy0.7Fe1.95 as an active element in a mechanically controlled break-junction device. The nanocontacts are reproducibly switched at room temperature between "open" (zero conductance) and "closed" (nonzero conductance) states by variation of a magnetic field applied perpendicularly to the long wire axis. Conductance measurements in a magnetic field oriented parallel to the long wire axis exhibit a different behaviour where the conductance switches between both states only in a limited field range close to the coercive field. Investigating the conductance in the regime of electron tunneling by mechanical or magnetostrictive control of the electrode separation enables an estimation of the magnetostriction. The present results pave the way to utilize the material in devices based on nano-electromechanical systems operating at room temperature.

No MeSH data available.


Related in: MedlinePlus