Helical spin structure in iron chains with hybridized boundaries
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- Univ. of California, San Diego, CA (United States)
- Univ. de Chile, Santiago (Chile); Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Santiago (Chile)
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Univ. of Texas at San Antonio, TX (United States); General Atomics, San Diego, CA (United States)
In this paper, we have compared the magnetic properties of well-controlled ultra-short (≤50 nm) atomic iron (Fe) chains embedded in Fe-phthalocyanine films with those in Fe–hydrogen (H2) phthalocyanine superlattices. Surprisingly, we found that the coercivity of the atomic chains with free boundary conditions is independent of the chain length, whereas the one subject to hybridization of the chain ends exhibits an unexpected length dependence. These findings suggest that ferromagnetism in the free-boundary condition system is caused by an intrinsic indirect exchange. On the other hand, controlled boundary conditions produce a helical spin structure due to an extrinsic indirect exchange, which arises from the interaction between iron atoms at the ends of the chain and the hydrogen in the H2 phthalocyanine spacer. As a consequence, during magnetic reversal, ultra-short iron chains subject to boundary clamping develop a helical spin structure, leading to increased coercivity. These findings suggest unique insights and ideas for the design of atomic-scale ultra-dense magnetic storage nanodevices.
- Research Organization:
- Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA); USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE Office of Science (SC); National Science Foundation (NSF)
- Grant/Contract Number:
- AC52-07NA27344; DMR 1805585; DMR 1804414; FA9550-161-0122; FA9550-18-1-0438; 19-LW-028; AC02-05CH11231; AC5207NA27344
- OSTI ID:
- 1724325
- Alternate ID(s):
- OSTI ID: 1970603
- Report Number(s):
- LLNL-JRNL-768283; 958148; TRN: US2204851
- Journal Information:
- Applied Physics Letters, Vol. 117, Issue 21; ISSN 0003-6951
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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