Detection of Rashba field using a rotational applied field

Title
Detection of Rashba field using a rotational applied field
Authors
장현철박윤호구현철김형준장준연김희중
Keywords
Potentiometric measurement; Rashba effect
Issue Date
2010-11
Publisher
55th Annual Conference on Magnetism and Magnetic Materials
Citation
, 255-255
Abstract
The Rashba field is an important factor to implement a spin transistor because the spin precession angle is determined by the strength of the Rashba field [1]. In order to measure the intrinsic Rashba field of an InAs quantum well, we utilize a circular shaped permalloy electrode (FM) using potentiometric geometry [2] in which the FM detect the Rashba spin splitting. When the rotational field (Ba) is applied in x-y plane, the voltage difference between FM and InAs channel is detected as shown in Fig. 1(a). The markers of Fig. 1(b) show the experimental results with a rotational field of Ba = 0.005 T. In this case, the applied field does not affect the Rashba field but it is large enough to saturate the FM magnetization to the field direction. The detected RPM (= V/I) is decided by the alignment between the Rashba field and the magnetization direction of FM. At θ = 90° (270°), the magnetization of FM is antiparallel (parallel) to the Rashba field, which is –y direction in this structure, so that the RPM indicates a minimum (maximum) value. This curve is cosine form and the amplitude is defined as RA, which is proportional to the strength of the Rashba field. If Ba is larger, the total field inside the channel should be calculated by the sum of Ba and the Rashba field. The amount of shift (ΔRS) is linearly increased with Ba and we found that the ratio of ΔRS/ΔBa is 0.032 Ω/T. If the Ba is same as the Rashba field, the curve should be shifted by RA. From the data in Fig. 1(b), RA is 0.289 Ω and therefore Ba = 9 T is required. In this method, we can estimate 9 T of Rashba field which is similar to the value obtained from the Shubnikov-de Haas oscillation measurement.
URI
http://pubs.kist.re.kr/handle/201004/38873
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KIST Publication > Conference Paper
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