Perpendicularizing magnetic anisotropy of full-Heusler Co2FeAl films by cosputtering with terbium

Abstract

In this letter, we fabricated Co2FeAl films with perpendicular-to-plane magnetic anisotropy by cosputtering with terbium (Tb). The as-prepared (Tb+Co2FeAl) films (TCFA) consists of nanocrystalline L21 Co2FeAl and amorphous alloy of Tb(Co, Fe, and Al). The coercivity field (Hc) of the TCFA films is adjustable from 200 to 800 Oe. After annealing, the Hc decreases to 70 Oe. A perpendicularly magnetized spin valve with the TCFA films as free and reference layers shows a current-perpendicular-to-plane magnetoresistance of 1.8% at room temperature. Our result opens a way to fabricate perpendicularly magnetized full-Heusler alloys and makes it possible to realize faster and simple structured magnetic storage bits in the future.

Magnetic properties of co-sputtered Tb–Co2FeAl films with perpendicular anisotropy

“…The H C is related with the antiferromagnetic coupling between Tb 4f and Fe (Co) 3d electrons that is also an important factor for PMA [9]. The PMA of CFA originates from the coupling with perpendicularly magnetized amorphous (Tb, Co, Fe, and Al) phase [14], and the PMA of the amorphous alloy mainly comes from the antiparallel coupling between 3d TM and Tb magnetic moment and the Tb moment aligns toward magnetic field, which is evidenced by magnetic Compton scattering in TbCoFe films [15]. Therefore, the content of Tb must affect the strength of coupling in TCFA films.…”

“…In our previous report, we have successfully fabricated perpendicularly magnetized HMFs thin films using full-Heusler alloy Co 2 FeAl co-sputtered with Tb [14]. In this paper, we present a further study on magnetic properties of the co-sputtered Tb-Co 2 FeAl (TCFA) films.…”

Data Storage: Review of Heusler Compounds

“…71,72 This is of crucial importance to the reduction of the switching current and power consumption of the current STT devices. Remarkably, perpendicular magnetic anisotropy (PMA) has recently been reported in the CFA-based epitaxial stacking structures, [73][74][75][76][77] suggesting the feasibility of the application of CFA in the perpendicular FM electrodes of MTJs with high thermal stability at reduced dimension. Other than the well-known cubic full-Heusler compounds, a family of tetragonally-distorted Heusler compounds Mn 2 YZ have recently emerged as another category of suitable materials due to their almost excellent fulfillment of the requirements for the electrodes of STT devices.…”

Anomalous Hall effect in perpendicularly magnetized thin films

“…Another approach to induce a perpendicular magnetic anisotropy is the utilization of ferromagnetic materials in combination with rare earth elements. The integration of such films into so-called perpendicular MTJs (pMTJs) or spin valves (SPVs) was reported by Nakayama et al [4] and Li et al [5] for Tb+CoFe and Tb+Co 2 FeAl.…”