280 research outputs found
The loss of material from the cathode of metal arcs
A study was made of the effect of arc length, cathode thickness, current strength, gas pressure and the chemical nature of the cathode material and filling gases upon the material loss from Cu, Fe, and Ag cathodes in arcs. The results show that the analysis of the phenomenon is complex and the energy balance is difficult to formulate
Parity effect in ground state localization of antiferromagnetic chains coupled to a ferromagnet
We investigate the ground states of antiferromagnetic Mn nanochains on
Ni(110) by spin-polarized scanning tunneling microscopy in combination with
theory. While the ferrimagnetic linear trimer experimentally shows the
predicted collinear classical ground state, no magnetic contrast was observed
for dimers and tetramers where non-collinear structures were expected based on
ab-initio theory. This striking observation can be explained by zero-point
energy motion for even numbered chains derived within a classical equation of
motion leading to non classical ground states. Thus, depending on the parity of
the chain length, the system shows a classical or a quantum behavior.Comment: 5 pages, 4 figures and supplementary informatio
Resolving the spin polarization and magnetic domain wall width of (Nd,Dy)FeB with spin-polarized scanning tunneling microscopy
The electronic structure and the domain wall width of industrial (Nd,Dy)FeB hard magnets were investigated using low-temperature, spin-polarized scanning tunneling microscopy (STM) in ultra-high vacuum. In a first step, atomically clean and flat surfaces were prepared. The flat terraces were separated by monatomic steps. Surface termination was identified as the Fe c layer from atomically resolved STM imaging. The electronic density of states and its spin polarization agree well with ab initio predictions of the Fe c layer. High-resolution spin-polarized STM images allowed to finally resolve the domain wall width w of only 3.2 ± 0.4 nm
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