Conductance Switching and Tunneling Characteristics of Remotely Controlled Magnetostriction-Based Nanocontacts

We demonstrate the utilization of the giant magnetostriction of Tb_0.3Dy_0.7Fe_1.95 in a mechanically controlled break-junction device to control the conductance in a remote way by variation of an applied magnetic field H at room temperature. The Tb_0.3Dy_0.7Fe_1.95 grain-oriented compound was obtained by employing a modified Bridgman method. The rod was grown with a preferred crystallographic orientation with <; 110> axes along the rod axis. Reproducible switching of the electrical conductance was observed at room temperature with the externally applied magnetic field perpendicularly to the wire long axis. Below 70 K, we observe a hysteresis for the conductance switching which is attributed to the pinning of domain walls. The switching of the conductance is distinctly different when the magnetic field is applied in the parallel or perpendicular direction with respect to the long wire axis, which is attributed to the different magnetic anisotropy in the two orientations. We also discuss about the tunneling characteristics of the Tb_0.3Dy_0.7Fe_1.95 nanocontacts at 10 K. These results are important for developing a device based on a nano-electromechanical system operating at room temperature.