Enhanced exchange and reduced magnetization of Gd in an Fe/Gd/Fe trilayer

Abstract

The exchange interaction of Gd adjacent to Fe has been characterized by transport measurements on a double spin valve with a Fe/Gd/Fe trilayer as the middle layer. Our measurements show that the ferromagnetism of the Gd is enhanced by the presence of the Fe, and it remains ferromagnetic over its Curie temperature up to a thickness no smaller than 1 nm adjacent to the Fe. This thickness is more than double what has been reported before. Additionally, the saturation magnetization of the thin Gd layer sandwiched in Fe was found to be half of its bulk value. This reduced magnetization does not seem to be related to the proximity of Fe but rather to the incomplete saturation of Gd even for very high fields.

Interlayer coupling in Fe/Cr/Gd multilayer structures

“…The reduction of layer magne tization is usually at most 20-30%. A similar strong decrease in the magnetization was detected in [28] for the Fe/Gd/Fe system: it was found that ≈ 1545 G and ≈ 1030 G. A more than twofold decrease in the magnetization of thin Gd layers as compared to the tab ulated value was also detected for the Gd/Cr multilayer system [29]. The suppression of the magnetization of Gd in the Gd/Cr/FeCo system in [20] was related to the presence of a paramagnetic crystalline fcc phase, which is nonequilibrium in bulk gadolinium.…”

Magnetization and ferromagnetic resonance in a Fe/Gd multilayer: experiment and modelling

“…Thus, the most probable reason for the observed strong reduction of magnetization seems to be due to a large degree of structural disorder and amorphousness of the grown FM layers. Indeed, such effects were previously reported for both thin polycrystalline Gd [27,28] and amorphous Fe layers [29]. In both cases the magnetization reduction can reach ∼ 50% of its bulk value.…”

The effect of annealing on magnetic properties of Co/Gd multilayers

“…At room temperature, bulk Gd is paramagnetic because of its low Curie temperature (292 K). Nevertheless, one has to notice that stabilization of ferromagnetism in Gd for temperature up to 350 K has already been reported and explained by the exchange coupling at the interface with Co [10][11]. In our case, Fig.…”

“…Indeed, the properties of RE/TM multilayers have been widely studied in the past [4][5][9][10][11] but the influence of heat treatment on the magnetic behavior of multilayers has not been enough researched. It has also been shown that interfacial magnetic disorder [12] impacts the magnetism and affects to the magnetization reversal processes [13].…”