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Co$_x$Zn$_{1-x}$O – Permalloy (Py) heterostructures were investigated with frequency-dependent ferromagnetic resonance (FMR), x-ray magnetic circular dichroism (XMCD) and SQUID magnetometry. At low temperatures Co$_x$Zn$_{1-x}$O is an uncompensated antiferromagnet showing a narrowly opened hysteresis and a vertical exchange-bias effect [1,2]. By means of SQUID a static interaction is evidenced by increased coercive fields for Py at low temperature in the Co$_x$Zn$_{1-x}$O – Py system. The dynamic interaction is measured by using FMR from 3-12GHz. We find an increasing frequency dependence of the homogeneous broadening of the FMR linewidth with increasing Co concentration evidencing spin pumping from Py into Co$_x$Zn$_{1-x}$O.
[1] V. Ney et al., Phys. Rev. B 94, 224405 (2016).
[2] M. Buchner et al., Phys. Rev. B 99, 064409 (2019)
