Magnetoresistance study in Co–Al–Co and Al–Co–Al double tunneling junctions

Abstract

Magnetoresistance (MR) in Co–Al–Co and Al–Co–Al double tunneling junctions has been studied at temperatures between 65 and 750 mK and in magnetic fields up to 3 T. The electrical resistance decreases with increasing temperature. In the low magnetic field region, the electrical resistance hysteresis behavior is attributed to a typical TMR for ferromagnetic Co and insulator Al2O3 elements. In the high magnetic field region, a sharp resistance variation roughly near 2.0 T for the Co–Al–Co system and 1.75 T for the Al–Co–Al system has been observed and is attributed to the electron tunneling effect. From the current–voltage and dI/dV characteristics, the superconductivity energy gap is roughly 0.5 meV in the Co–Al–Co system and roughly 0.3 meV in the Al–Co–Al system; and magnetic tunneling energy is roughly 0.01 meV in the Co–Al–Co system and roughly 0.06 meV in the Al–Co–Al system.

Growth and structure characterization of EuSi 2 films and nanoislands on vicinal Si(001) surface

“…A special attention has been paid on the stabilization of RE silicide nanowires with high aspect ratio. Up to now Dy [1 4], Ho [4], Er [5], Gd [6], and Sm [7] have been reported to self assemble in parallel nanowires on vicinal Si(001), while on the planar Si(001) surface the nanowires self organize along two orthogonal directions [8]. By changing the growth temperature 3D RE silicide nanoislands and clusters have been formed [1,9].…”

Spin effects in single-electron tunnelling

“…First ferromagnetic single-electron transistors were fabricated by Ono et al [25,26] and later by Brückl et al [27]. Transport in ferromagnetic single-electron transistors with nonmagnetic metallic islands -both normal and superconducting -was also measured [28,29,30,31]. One should bear in mind, that the interplay of spin and charge effects was already studied long time ago in granular systems, in which magnetic nanoparticles were randomly dispersed in a nonmagnetic matrix [32].…”

Quantum Dots Attached to Ferromagnetic Leads: Exchange Field, Spin Precession, and Kondo Effect

“…All-ferromagnetic metallic single-electron transistors have been manufactured, using either single-island [13,14], or multi-island structures [15,16]. Magnetoresistance of single-electron transistors with a normal metallic island in a cobalt-aluminum-cobalt structure has been measured [17]. In all these examples, the level spectrum on the island is continuous, and many levels are involved in transport.…”