Synthetic domain walls in [TbFeGa/TbFe]₂ multilayers

Abstract

Here we report the possibility of creating synthetic domain walls in nominal [Fe72Ga28/Tb33Fe67]2 multilayers. The magnetization as a function of the temperature reveals the absence of Compensation temperature in the samples which can be understood considering an interdiffusion process that results in the formation of TbFeGa alloys at the nominal FeGa layers. Therefore, samples are actually comprised of TbFeGa and TbFe layers. The hysteresis loops exhibit magnetization steps related to the nucleation of domain walls formed because of the competition between different interactions: i) the antiferromagnetic exchange coupling between the heavy rare earth (Tb) and the transition magnetic metal (Fe) inside each layer, ii) the antiferromagnetic coupling between Tb and Fe at the interfaces, and iii) the Zeeman energy. In good agreement with the experimental values, the nucleation field of the domain walls has been theoretically calculated taking into account the tilt of the magnetization with respect to the sample plane. Our experimental results indicate that by a proper thickness adjustment, it can be tuned both, the value of the nucleation field, and the layer in which this firstly occurs. Experimental values for the exchange bias field have also been calculated.

Interfacial coupling effect of Cr2O3 on the magnetic properties of Fe72Ga28 thin films

“…Although Cr 2 O 3 has already been coupled with ferromagnetic metals 30 – 32 , the interaction with Fe 72 Ga 28 seems not a trivial problem. Fe 72 Ga 28 has already been coupled with TbFe 2 in [Fe 72 Ga 28 /TbFe 2 ] multilayers to turn its magnetization into the OOP direction 33 , 34 . However, only a tilt of the magnetization of around 25° with respect to the sample plane was achieved despite the large PMA of TbFe 2 33 , 34 .…”

“…Fe 72 Ga 28 has already been coupled with TbFe 2 in [Fe 72 Ga 28 /TbFe 2 ] multilayers to turn its magnetization into the OOP direction 33 , 34 . However, only a tilt of the magnetization of around 25° with respect to the sample plane was achieved despite the large PMA of TbFe 2 33 , 34 . Here we show that by means of a suitable experiment design in terms of layer thickness and materials, it is possible to reach an effective interfacial interaction that enables to turn the Fe 72 Ga 28 magnetization into the OOP direction.…”

Interfacial coupling effect of Cr2O3 on the magnetic properties of Fe72Ga28 thin films

“…Although Cr 2 O 3 has already been coupled with ferromagnetic metals [30][31][32], the interaction with Fe 72 Ga 28 seems not a trivial problem. Fe 72 Ga 28 has already been coupled with TbFe 2 in [Fe 72 Ga 28 /TbFe 2 ] multilayers to turn its magnetization into the OOP direction [33][34]. However, only a tilt of the magnetization of around 25° with respect to the sample plane was achieved despite the large PMA of TbFe 2 [33][34].…”

“…Fe 72 Ga 28 has already been coupled with TbFe 2 in [Fe 72 Ga 28 /TbFe 2 ] multilayers to turn its magnetization into the OOP direction [33][34]. However, only a tilt of the magnetization of around 25° with respect to the sample plane was achieved despite the large PMA of TbFe 2 [33][34]. Here we show that thanks to an appropriate election of layer thickness and coupling material, it is possible to reach an effective interfacial interaction that enables to turn the Fe 72 Ga 28 magnetization into the OOP direction.…”