A unique and important property of the neutron is that it possesses magnetic moment. This property is widely used for determination of magnetic structure of crystalline samples observing the magnetic components of the diffraction peaks. Investigations of diffraction patterns give information only about the averaged structure of a crystal but for discovering of local spin arrangement around a specific (e.g., impurity) nucleus remains still a challenging problem. Neutron holography is a useful tool to investigate the local structure around a specific nucleus embedded in a crystal lattice. The method has been successfully applied experimentally in several cases using non-magnetic short range interaction of the neutron and the nucleus. A mathematical model of the hologram using interaction between magnetic moment of the atom and the neutron spin for polarized neutron holography is provided. Validity of a polarized neutron holographic experiment is demonstrated by applying the proposed method on model systems. V C 2015 AIP Publishing LLC. [http://dx.A common property of diffraction methods is that they measure the averaged structure of the entire sample and they provide limited information on the local structure around a specific nucleus, e.g., an impurity atom. Atomic resolution holography is a special method for direct imaging of the structure around a selected atom. Holograms with atomic resolution have been recorded applying various kinds of de Broglie waves, e.g., electrons, 1 X-rays, 2 or neutrons. 3-5 These methods always need an incorporated source or a detector of the radiation inside the sample, 6 thus two types of holography can be distinguished: inside source holography (ISH) and inside detector holography (IDH). In the following, we consider only the IDH case. In this case, a part of the incoming plane wave directly reaches the detector atom and other parts of plane wave are scattered on the neighbourhood of the detector atom before reaching it. The interference pattern is recorded in the position of the detector atom by emission of a characteristic radiation. The intensity of the radiation emitted by the detector atom is proportional to the intensity of the interference pattern at the position of detector nucleus. Interference pattern is scanned by changing the sample orientation.These properties mentioned above are independent from the type of used radiation. Neutron holography is useful because neutrons have some particular properties, such as interaction with the nucleus (especially with the hydrogen nucleus), high penetration depth, and possession of magnetic dipole moment, which make them unique probes for structural studies.Neutrons interact with the magnetic moment of atoms in a crystal through the neutron spin, allowing them to carry out magnetic neutron holography (MNH). This advantage has been mentioned in Refs. 7 and 8, but no detailed study about the expected hologram was given.Cadmium, boron, and gadolinium can be effectively used as inside detector nuclei because of their rather high absorp...

Reliability and lifetime are the two most relevant design considerations in the production of safety critical assemblies. For example in a modern automobile dozens of electronic assemblies are integrated in which thousands of solder joints are mounting the electronic components to the printed circuit boards. There exists no standardised and universal observation method for characterising the fine microstructure of such solder joints. Previously we have developed a new method for the quantitative characterization of lead-free solder alloys and in present study the validity of the proposed method is demonstrated. Microstructure of Sn-3.5Ag lead free solder alloy was investigated by electrochemical impedance spectroscopy. Solder samples were solidified with different cooling rates in order to induce differences in the microstructure. Microstructure of the ingots was revealed by selective electrochemical etching. Electrochemical impedance spectra (EIS) were measured before and after the selective etching process. The complex impedance spectra contain information about microstructure of the solder alloys. Comparison and modelling of two EIS spectra allowed obtaining a characteristic parameter of surface structure of the etched specimens. The EIS measurements were complemented with small angle neutron scattering measurements and scanning electron microscopy, in order to correlate the EIS parameter with the magnitude of the interface of the β-Sn and Ag3Sn phases.

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