다음과 같이 세미나 모임을 개최합니다. 많은 참석 부탁합니다. 

날짜: 2015/ 6/2 (화)

장소: 삼성 학술 정보관 2층 스터디룸 2F-6

연사: 박  수  현  박사님 (서울대학교 IBS 강상관계물질연구단)

제목: Helical magnetic order in Fe nanoislands

초록: Magnetic interfaces show intriguing phenomena, such as exchange bias, tuning of magnetic
anisotropy, and spin information transfer. However, low-dimensionality in magnetic materials,
as compared to their bulk counterparts, often leads to unconventional magnetic behaviors such
as non-collinear spin orders[1]. Elaborate studies on nanoscale magnets, thus, are required to
utilize the magnetic nanocontacts for envisioned applications to future spin transport device and
data-storage. We employ spin-polarized scanning tunneling microscopy and spectroscopy (SPSTM/
S) to achieve a microscopic access to the local magnetic properties in individual
nanostructures.
In this talk, I present SP-STM/S studies on nanostructures of bilayer Fe[1], Co[2], and their spin
interfaces on Cu(111)[3,4], with control and quantitative characterization of magnetic states of
tips[5]. First, Fe nanoisland shows a magnetic stripe phase with a period of 1.28 nm (Fig. 1), which
is identified as a one-dimensional helical spin order.[1] Ab initio calculations identify reduceddimensionality-
enhanced competing exchange interactions as the driving force of this spin order.
Second, SP-STM/S of Co in a circumferential contact with Fe[3] (Fig. 2) reveals interfacial
variations of magnetic orders of both sides, concurrent with a switching between two distinct
bound phases of Fe helical spin order by bistable Co ferromagnetic (FM) states.[4] Spin
polarization mapping provides an atomic scale spatial spin distribution in proximity of the Co-Fe
contact, which may unravel the magnetic coupling responsible for the interfacial magnetic order.