A. Sonntag
University of Hamburg
11 Papers
97 Citations
A. Sonntag is an academic researcher from University of Hamburg. The author has contributed to research in topics: Scanning tunneling microscope & Magnetic field. The author has an hindex of 7, co-authored 11 publications.
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Papers
Electric-field-induced magnetic anisotropy in a nanomagnet investigated on the atomic scale.
TL;DR: It is concluded that the electric field E induces a uniaxial anisotropy that favors in-plane magnetization for E<0 and out-of-plane magnets for E>0.
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Design and performance of an ultra-high vacuum spin-polarized scanning tunneling microscope operating at 30 mK and in a vector magnetic field
Henning von Allwörden,Andreas Eich,Elze J. Knol,Jan Hermenau,A. Sonntag,Jan W. Gerritsen,Daniel Wegner,Alexander A. Khajetoorians +7 more
TL;DR: The design and performance of a scanning tunneling microscope (STM) that operates at a base temperature of 30 mK in a vector magnetic field and spin resolution by imaging the magnetic structure of the Fe double layer on W(110) is described.
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Design and performance of an ultra-high vacuum spin-polarized scanning tunneling microscope operating at 30 mK and in a vector magnetic field.
Henning von Allwörden,Andreas Eich,Elze J. Knol,Jan Hermenau,A. Sonntag,Jan W. Gerritsen,Daniel Wegner,Alexander A. Khajetoorians +7 more
Abstract: We describe the design and performance of a scanning tunneling microscope (STM) that operates at a base temperature of 30 mK in a vector magnetic field The cryogenics is based on an ultra-high vacuum (UHV) top-loading wet dilution refrigerator that contains a vector magnet allowing for fields up to 9 T perpendicular and 4 T parallel to the sample The STM is placed in a multi-chamber UHV system, which allows in situ preparation and exchange of samples and tips The entire system rests on a 150-ton concrete block suspended by pneumatic isolators, which is housed in an acoustically isolated and electromagnetically shielded laboratory optimized for extremely low noise scanning probe measurements We demonstrate the overall performance by illustrating atomic resolution and quasiparticle interference imaging and detail the vibrational noise of both the laboratory and microscope We also determine the electron temperature via measurement of the superconducting gap of Re(0001) and illustrate magnetic field-dependent measurements of the spin excitations of individual Fe atoms on Pt(111) Finally, we demonstrate spin resolution by imaging the magnetic structure of the Fe double layer on W(110)
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Joule heating and spin-transfer torque investigated on the atomic scale using a spin-polarized scanning tunneling microscope.
TL;DR: A detailed lifetime analysis allows for a quantification of the effective temperature rise of the nanoisland and the modification of the activation energy barrier for magnetization reversal, thereby using the nano island as a local thermometer and spin-transfer torque analyzer.
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Individual atomic-scale magnets interacting with spin-polarized field-emitted electrons.
TL;DR: On a quasistable nanomagnet, a spin-polarized emission current in the low nA regime already triggers magnetization reversal, thereby demonstrating the high impact of hot-electron spins onto atomic-scale magnets.
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