In-plane magnetotransport properties of Permalloy∕gadolinium∕Permalloy trilayers

Abstract

In this work we report on the magnetic and electrical properties of Permalloy/gadolinium/Permalloy ͑Py/Gd/Py͒ trilayers at low temperatures. These results are complemented with a structural study and numerical calculations. The Py-Gd coupling field is derived from magnetoresistance measurements in the transverse configuration of the trilayer with a Permalloy thickness lower than its exchange correlation length. The coupling field obtained was low, likely due to the presence of low Curie temperature Gd 1−x Ni x alloys at the Py/Gd interfaces.

Influence of the Fe content on the Gd magnetic ordering temperature in Ni1−xFex/Gd multilayers

“…This is not the case, however, in Gd/Ni multilayer films without interfacial alloy formation, where the magnetic moment of Gd was measured by XMCD up to room temperature. 22 Then, the presence of a Gd-Ni alloy, which might be localized at the Ni-Fe/Gd interfaces, 23,24 is not consistent with the observation of Gd magnetization above room temperature in our samples, at least not in a laterally homogeneous sample. In addition, our data show negligible temperature dependence of Ni and Fe XMCD signals, so the presence of Gd-Ni alloys with a low T C can be ruled out.…”

Enhanced spin pumping near a magnetic ordering transition

“…1. The magnetic response is seen to be quite complex, due to the superposition of Gd finite size effects and strong Py-Gd interlayer coupling, which is known to generate high saturation fields 27,37,38 antiferromagnetic interactions, and non-collinear spin states 39 . Specifically, Py(10 nm)/Gd(3 nm) bilayers exhibit soft ferromagnetic behavior above 200 K with negligible coercivity and 95 % of the saturation magnetization (M s ) being reached in only 1 kOe.…”

Heterostructured ferromagnet–topological insulator with dual-phase magnetic properties

“…Ni 80 Fe 20 permalloy (Py) is renowned for its permeability, 16,17 low coercivity, 16,18,19 near zero magnetostriction 20,21 and ease of fabrication using inexpensive methods. Mellnik et al 15 recently demonstrated spin-transfer torque (STT) generated by a Py/ Bi 2 Se 3 heterostructure device.…”