Zero-field spin torque oscillation in Co2(Fe, Mn)Si with a point contact geometry

We show spin torque oscillation at zero external magnetic field using a point-contact giant magnetoresistance device with a highly spin-polarized Co2Fe0.4Mn0.6Si (CFMS) Heusler alloy. The device emitted a high rf power (P-rf) signal with a narrow spectral linewidth of 3 MHz without external magnetic field. Depending on the applied current, mode changes were clearly observed, and a large P-rf of 25.7 nW was achieved. The large P-rf and the high coherency of oscillation are attributable to the combination of the high spin-polarization of CFMS and the advantages of point-contact geometry. (C) 2015 AIP Publishing LLC.