The origin of the uniaxial magnetic anisotropy in Fe/GaAs(100) system

TY - JOUR

T1 - The origin of the uniaxial magnetic anisotropy in Fe/GaAs(100) system

AU - Yan, Yu

AU - Liu, Bo

AU - Lu, Xianyang

AU - Wang, Junlin

AU - Dhesi, Sarnjeet S.

AU - Will, Iain G.

AU - Lazarov, Vlado K.

AU - Du, Jun

AU - Wu, Jing

AU - Zhang, Rong

AU - Xu, Yongbing

N1 - Publisher Copyright: © 2025 Author(s).

PY - 2025/3/7

Y1 - 2025/3/7

N2 - Fe/GaAs is a prototype system of spin injection at room temperature. The interfacial strain and oriented bonds are both considered the origin of the Fe in-plane uniaxial magnetic anisotropy (UMA), which remains decisive. Here, by the x-ray magnetic circular dichroism (XMCD) and the vibrating sample magnetometer measurements, this study shows that in the Fe/Cr(t)/GaAs structure, the in-plane UMA of Fe originates from the chemical bonding between the Fe and the GaAs substrate by varying Cr thickness, t. The UMA drops as the Cr coverage increases, characterized by a decrease in the saturation field from 2400 to 57 Oe. The XMCD studies reveal that the Fe orbital moment, a signature of chemical bonds, decreases from 0.216 μB at Cr = 0 ML to 0.138 μB at Cr = 5 ML. The reduction of the Fe orbital moment and the UMA are qualitatively consistent, establishing a link between the UMA and the interfacial chemical bonds. The decreased UMA remains unchanged at t > 5 ML, above which Fe and GaAs are fully separated by a continuous Cr layer. Our findings provide clear experimental evidence that the UMA in the Fe/GaAs system originates from the oriented interface bonds, clarifying the UMA origin in this prototype system.

AB - Fe/GaAs is a prototype system of spin injection at room temperature. The interfacial strain and oriented bonds are both considered the origin of the Fe in-plane uniaxial magnetic anisotropy (UMA), which remains decisive. Here, by the x-ray magnetic circular dichroism (XMCD) and the vibrating sample magnetometer measurements, this study shows that in the Fe/Cr(t)/GaAs structure, the in-plane UMA of Fe originates from the chemical bonding between the Fe and the GaAs substrate by varying Cr thickness, t. The UMA drops as the Cr coverage increases, characterized by a decrease in the saturation field from 2400 to 57 Oe. The XMCD studies reveal that the Fe orbital moment, a signature of chemical bonds, decreases from 0.216 μB at Cr = 0 ML to 0.138 μB at Cr = 5 ML. The reduction of the Fe orbital moment and the UMA are qualitatively consistent, establishing a link between the UMA and the interfacial chemical bonds. The decreased UMA remains unchanged at t > 5 ML, above which Fe and GaAs are fully separated by a continuous Cr layer. Our findings provide clear experimental evidence that the UMA in the Fe/GaAs system originates from the oriented interface bonds, clarifying the UMA origin in this prototype system.

UR - http://www.scopus.com/inward/record.url?scp=86000180200&partnerID=8YFLogxK

U2 - 10.1063/5.0253345

DO - 10.1063/5.0253345

M3 - Article

AN - SCOPUS:86000180200

SN - 0003-6951

VL - 126

JO - Applied Physics Letters

JF - Applied Physics Letters

IS - 9

M1 - 092410

ER -