TY - JOUR
T1 - Reduction of critical current density for out-of-plane mode oscillation in a mag-flip spin torque oscillator using highly spin-polarized Co2Fe(Ga0.5Ge0.5) spin injection layer
AU - Bosu, S.
AU - Sepehri-Amin, H.
AU - Sakuraba, Y.
AU - Hayashi, M.
AU - Abert, C.
AU - Suess, D.
AU - Schrefl, T.
AU - Hono, K.
N1 - Publisher Copyright:
© 2016 AIP Publishing LLC.
PY - 2016/2/15
Y1 - 2016/2/15
N2 - 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.
AB - 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.
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U2 - 10.1063/1.4942373
DO - 10.1063/1.4942373
M3 - Article
AN - SCOPUS:84960923326
SN - 0003-6951
VL - 108
JO - Applied Physics Letters
JF - Applied Physics Letters
IS - 7
M1 - 072403
ER -