-
Ion irradiation-induced sinking of Ag nanocubes into substrates
Authors:
Shiva Choupanian,
Wolfhard Moeller,
Martin Seyring,
Claudia Pacholski,
Elke Wendler,
Andreas Undisz,
Carsten Ronning
Abstract:
Ion irradiation can cause burrowing of nanoparticles in substrates, strongly depending on the material properties and irradiation parameters. In this study, we demonstrate that the sinking process can be accomplished with ion irradiation of cube-shaped Ag nanoparticles on top of silicon; how ion channeling affects the sinking rate; and underline the importance of the amorphous state of the substra…
▽ More
Ion irradiation can cause burrowing of nanoparticles in substrates, strongly depending on the material properties and irradiation parameters. In this study, we demonstrate that the sinking process can be accomplished with ion irradiation of cube-shaped Ag nanoparticles on top of silicon; how ion channeling affects the sinking rate; and underline the importance of the amorphous state of the substrate upon ion irradiation. Based on our experimental findings, the sinking process is described as being driven by capillary forces enabled by ion-induced plastic flow of the substrate.
△ Less
Submitted 30 May, 2023;
originally announced May 2023.
-
Low damping and microstructural perfection of sub-40nm-thin yttrium iron garnet films grown by liquid phase epitaxy
Authors:
Carsten Dubs,
Oleksii Surzhenko,
Ronny Thomas,
Julia Osten,
Tobias Schneider,
Kilian Lenz,
Jörg Grenzer,
René Hübner,
Elke Wendler
Abstract:
The field of magnon spintronics is experiencing an increasing interest in the development of solutions for spin-wave-based data transport and processing technologies that are complementary or alternative to modern CMOS architectures. Nanometer-thin yttrium iron garnet (YIG) films have been the gold standard for insulator-based spintronics to date, but a potential process technology that can delive…
▽ More
The field of magnon spintronics is experiencing an increasing interest in the development of solutions for spin-wave-based data transport and processing technologies that are complementary or alternative to modern CMOS architectures. Nanometer-thin yttrium iron garnet (YIG) films have been the gold standard for insulator-based spintronics to date, but a potential process technology that can deliver perfect, homogeneous large-diameter films is still lacking. We report that liquid phase epitaxy (LPE) enables the deposition of nanometer-thin YIG films with low ferromagnetic resonance losses and consistently high magnetic quality down to a thickness of 20 nm. The obtained epitaxial films are characterized by an ideal stoichiometry and perfect film lattices, which show neither significant compositional strain nor geometric mosaicity, but sharp interfaces. Their magneto-static and dynamic behavior is similar to that of single crystalline bulk YIG. We found, that the Gilbert damping coefficient alpha is independent of the film thickness and close to 1 x 10-4, and that together with an inhomogeneous peak-to-peak linewidth broadening of delta H0|| = 0.4 G, these values are among the lowest ever reported for YIG films with a thickness smaller than 40 nm. These results suggest, that nanometer-thin LPE films can be used to fabricate nano- and micro-scaled circuits with the required quality for magnonic devices. The LPE technique is easily scalable to YIG sample diameters of several inches.
△ Less
Submitted 21 November, 2019;
originally announced November 2019.
-
Defect-induced magnetism in SiC: Interplay between ferromagnetism and paramagnetism
Authors:
Yutian Wang,
Yu Liu,
Elke Wendler,
René Hübner,
Wolfgang Anwand,
Gang Wang,
Xuliang Chen,
Wei Tong,
Zhaorong Yang,
Frans Munnik,
Gregor Bukalis,
Xiaolong Chen,
Sibylle Gemming,
Manfred Helm,
Shengqiang Zhou
Abstract:
Defect-induced ferromagnetism has triggered a lot of investigations and controversies. The major issue is that the induced ferromagnetic signal is so weak that it can sufficiently be accounted for by trace contamination. To resolve this issue, we studied the variation of the magnetic properties of SiC after neutron irradiation with fluence covering four orders of magnitude. A large paramagnetic co…
▽ More
Defect-induced ferromagnetism has triggered a lot of investigations and controversies. The major issue is that the induced ferromagnetic signal is so weak that it can sufficiently be accounted for by trace contamination. To resolve this issue, we studied the variation of the magnetic properties of SiC after neutron irradiation with fluence covering four orders of magnitude. A large paramagnetic component has been induced and scales up with defect concentration, which can be well accounted for by uncoupled divacancies. However, the ferromagnetic contribution is still weak and only appears in the low fluence range of neutrons or after annealing treatments. First-principles calculations hint towards a mutually exclusive role of the concentration of defects: Defects favor spin polarization at the expense of magnetic interaction. Combining both experimental and first-principles calculation results, the defect-induced ferromagnetism can be understood as a local effect which cannot be scaled up with the volume. Therefore, our investigation answers the long-standing question why the defect-induced ferromagnetic signal is weak.
△ Less
Submitted 10 November, 2015; v1 submitted 6 January, 2015;
originally announced January 2015.