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[14p-P10-54] Influence of Pt and Au spacer layer on perpendicular exchange bias and oercivity
in Pt/Co/spacer/Cr2O3/Pt stacked films
Keywords:perperdicular exchange bias, interfacial magnetic anisotropy
The perpendicular exchange bias (PEB), appeared in the interface between ferromagnetic (FM) and antiferromagnetic (AFM) materials, is of vital importance to realize modern spintronic devices, such as a spin valve with the advantages of high speed operation, high integration and low power consumption [1]. The PEB field (Hex), the magnetic field (H) shift from origin H=0 of magnetization curve, can be controlled by tuning the interface exchange interaction. Previous studies showed the enhancement in Hex by inserting a spacer layer, e.g., Pt, at the FM/AFM interface [2]. This, however, resulted in the increase of the coercivity (Hc) which was an obstacle for device applications. To have an actual system with a high Hex and a low Hc is still challenged.
This study investigates the influence of Pt and Au spacer layers on the Hex and Hc of stacking films: Pt/Co(0.4 nm or 0.6 nm)/(Pt or Au)(0.5 nm)/Cr2O3(150 nm)/Pt(20 nm) deposited on α-Al2O3 substrates using a DC magnetron sputtering. Structural characterizations were carried out using a reflection high-energy electron diffraction, an X-ray diffraction and an X-ray reflectivity. Magnetic properties were characterized by means of a vibrating sample magnetometer, a magneto-optic Kerr effect (MOKE) magnetometer, and a soft and a hard X-ray magnetic circular dichroism. Fig. 1 shows the temperature dependence of the Hex and Hc for typical samples (with similar 0.4-nm-thick Co layer) with Pt (Fig. 1a) and Au (Fig. 1b) spacers. The results showed that the Hex was highly degraded in the Pt-spacer sample, while that for the Au-spacer sample was significantly increased. Moreover, the Au spacer also suppressed the enhancement in Hc that usually occurs at around room temperature when using Pt. The difference in Hex is due to the in-plane interfacial magnetic anisotropy at the Pt/Cr2O3 interface, which cants the interfacial Cr spin from the surface normal and results in a degradation in the PEB. More details will be discussed in the presentation.
This study investigates the influence of Pt and Au spacer layers on the Hex and Hc of stacking films: Pt/Co(0.4 nm or 0.6 nm)/(Pt or Au)(0.5 nm)/Cr2O3(150 nm)/Pt(20 nm) deposited on α-Al2O3 substrates using a DC magnetron sputtering. Structural characterizations were carried out using a reflection high-energy electron diffraction, an X-ray diffraction and an X-ray reflectivity. Magnetic properties were characterized by means of a vibrating sample magnetometer, a magneto-optic Kerr effect (MOKE) magnetometer, and a soft and a hard X-ray magnetic circular dichroism. Fig. 1 shows the temperature dependence of the Hex and Hc for typical samples (with similar 0.4-nm-thick Co layer) with Pt (Fig. 1a) and Au (Fig. 1b) spacers. The results showed that the Hex was highly degraded in the Pt-spacer sample, while that for the Au-spacer sample was significantly increased. Moreover, the Au spacer also suppressed the enhancement in Hc that usually occurs at around room temperature when using Pt. The difference in Hex is due to the in-plane interfacial magnetic anisotropy at the Pt/Cr2O3 interface, which cants the interfacial Cr spin from the surface normal and results in a degradation in the PEB. More details will be discussed in the presentation.