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Current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) characteristics were investigated in a Co 2 MnSi (CMS)/Ag/CMS fully epitaxial device and compared to those in a CMS/Cr/CMS device systematically. Reflection high-energy electron diffraction and transmission electron microscopy images showed the two samples had no remarkable differences and little interdiffusion. The large spinasymmetry of electron scattering was found at the CMS/Ag inteface compared with that at the CMS/Cr interface. Finally, the largest magneto-resistance (MR) ratio of 28.8% was observed at room temperature in the CMS/Ag/CMS CPP-GMR device.

Fully epitaxial Co 2 Fe x Mn 1Àx Si(CFMS)/Ag/Co 2 Fe x Mn 1Àx Si current-perpendicular-to-plane giant magnetoresistive devices with various Fe/Mn ratios x and top CFMS layer thicknesses t CFMS were prepared. The highest magnetoresistance (MR) ratios, 58% at room temperature and 184% at 30 K, were observed in the sample with x ¼ 0.4 and t CFMS ¼ 3 nm. Enhancement of interface spinasymmetry was suggested for x ¼ 0.4 compared with that at x ¼ 0. A MR ratio of 58% was also observed even in a very thin trilayer structure, CFMS(4 nm)/Ag(3 nm)/CFMS(2 nm), which is promising for a next-generation magnetic read sensor for high-density hard disk drives. V

We study spin torque oscillators comprised of a perpendicular spin injection layer (SIL) and a planar field generating layer to reveal the influence of the spin polarization of SIL material on the critical current density, JC, to induce microwave oscillation. Two systems with different SIL are compared: one with a highly spin-polarized Heusler alloy, Co2Fe(Ga0.5Ge0.5) (CFGG), and the other a prototypical Fe2Co alloy. Cross sectional scanning transmission electron microscopy observations show the B2-ordered structure in a 3-nm-thick CFGG SIL, a prerequisite for obtaining half-metallic transport properties. Current induced microwave oscillations are found at frequencies of ∼15 GHz for both systems. However, the current needed to cause the oscillations is ∼50% smaller for films with the CFGG SIL compared to those of the Fe2Co SIL. These results are in accordance with micromagnetic simulations that include spin accumulation at the SIL.

Articles you may be interested inStructural, magnetic and electrical properties of ferromagnetic/ferroelectric multilayers J. Appl. Phys. 109, 123920 (2011) We model the charge, spin, and heat currents in ferromagnetic metaljnormal metaljnormal metal trilayer structures in the two current model, taking into account bulk and interface thermoelectric properties as well as Joule heating. The results include the temperature distribution as well as resistance-current curves that reproduce the observed shifted parabolic characteristics. Thin tunneling barriers can enhance the apparent Peltier cooling. The model agrees with the experimental results for wide multilayer pillars, but the giant effects observed for diameters Շ100 nm are still under discussion. V C 2016 AIP Publishing LLC. [http://dx

We study Peltier cooling in current-perpendicular-to-plane multilayer nanopillars with diameters D varying from 60 to 430 nm and made from Au and various ferromagnets (FMs): Heusler compounds Co2MnSi and Co2FeSi (CFS) and conventional FM metals Fe and Co. We report an enhanced effective Peltier coefficient ΠCPP in resistance–current curves at small D (<120 nm). The maximum ΠCPP value of about 165 mV, found for the CFS/Au interface with D ∼ 60 nm, is 24 times higher than the bulk Peltier coefficient Πbulk (∼7 mV) and corresponds to a high cooling power of 43.6 MW/cm2.

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