Current-driven switching of exchange biased spin-valve giant magnetoresistive nanopillars using a conducting nanoprobe

Abstract

An array of exchange biased spin-valve giant-magnetoresistance nanopillars was fabricated and the current I dependence of the resistance R was investigated using an electrically conducting atomic-force microscope (AFM) probe contact at room temperature. We observed current induced switching in a MnIr/ CoFe/ Cu/ CoFe/ NiFe nanopillar using the AFM probe contact. Current-driven switching using nanoprobe contact is a powerful method for developing nonvolatile and rewritable magnetic memory with high density.

In situ TEM studies of local transport and structure in nanoscale multilayer films

“…Scanning probe techniques such as conducting atomic force microscopy (c-AFM) and scanning tunneling microscopy (STM) have very high spatial resolution and have been used successfully to collect nanometer-scale site-specific transport information from multilayered nanoelectric systems [13,[15][16][17][18][19][20]. However, it is very hard to use these techniques to correlate local transport behavior with the interfacial microstructure at the exact measurement site because the sub-surface microstructure is not imaged directly, but is instead a convolution of the surface topography, electronic structure, and probe tip shape.…”

Giant magnetoresistance in lateral metallic nanostructures for spintronic applications

“…The failure to develop spintronic applications based on lateral structures is mainly due to the weakness of the spin signal amplitudes, when compared to what can be obtained in vertical devices. In the case of the giant magnetoresistance, the resistance variations in all-metallic pillars are usually of a few percent 7 , 8 (and to more than one hundred of percent using multilayers stacks 9 or magnetic tunnel junctions 10 ). As a comparison, GMR variations in LSVs are usually found to be of the order of magnitude of a percent 11 , 12 , or even less, for a spin signal amplitude of a few milliohms.…”

“…1b . These values have to be compared to GMR variations obtained using CPP measurements in equivalent nanopillars, e.g., in CoFe/Cu/CoFe 7 or Co/Ni 4 /Cu/Co/Ni 4 8 , which are found to be smaller (2.5% and 3.5%, respectively). This competitiveness of lateral devices pleads for their use in spintronics applications, knowing that further amplification means can be used, such as the use of magnetic tunnel juctions 16 or Heuslers alloys 15 .…”

Electrically conducting probes with full tungsten cantilever and tip for scanning probe applications

“…for Pt/iridium coated tips) and display I V characteristics that are not ohmic [20]. Due to the DLC CVD fabrication process the outer tip shape has a granular structure, which is inconvenient in KPM.…”

“…Several drawbacks are apparent: first, coating a probe results in loss of tip sharpness, which reduces the resolution obtained in operation. Second, metal coated probes with a typical coating's thickness of around 20-25 nm quickly lose their coating upon a tip crash, wear, or melting at high current densities [20]. Although the wear properties of B-doped DLC (coated) tips are excellent, they exhibit a high contact resistance of ∼4 k (compared to ∼100…”