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.
Highlights
With low anisotropy at room temperature[13,14,15,16,17,18,19]
The magnetostriction vs. magnetic field H is plotted in Fig. 1(b) which confirms a giant value of λ ≈ 1.5 × 10−3 in 0.4 Tesla at room temperature
The results clearly demonstrate the remote control of the nanocontact conductance by a magnetic field
Summary
With low anisotropy at room temperature[13,14,15,16,17,18,19]. Among these compounds, the rare-earth transition-metal compound (Tb0.27Dy0.73)Fe1.95 with cubic structure is commercially available as rods under the name Terfenol-D18. The material properties can be further tuned to obtain the anisotropy-compensated compound Tb0.3Dy0.7Fe1.95 with low first-order magnetocrystalline anisotropy constant K1 = − 6 × 104Jm−3 and huge magnetostriction λ = 1.6 × 10−3 at room temperature[20]. This material can be used in the form of wires to realize a magnetic-field operated “nanoswitch” at room temperature. Conductance measurements have been reported for single-element based atomic junctions but not for junctions comprising multi-element compounds[21,22], in particular not for devices exploiting giant-magnetostriction phenomena at room temperature. Comparison of the electron tunneling data when controlling the gap between two contacts either mechanically or by magnetic field allows an estimation of the magnetostriction of Tb0.3Dy0.7Fe1.95
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