Die titrimetrische Schnellbestimmung grosser Mengen Mangan in technischen Eisenlegierungen

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Nachweis und Bestimmung des Mangans sowie seine Trennung von anderen Elementen

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Kleine Beiträge zur Konstitution des Isochondodendrins und des Thebains

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Beitrag zur Bestimmung des Kupfers in Schwefelkiesen

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Magnetic indication of the stress-induced martensitic transformation in ferromagnetic Ni–Mn–Ga alloy

A quantitative study of the stress-induced martensitic transformation in Ni_49.7Mn_29.1Ga_21.2 magnetic shape memory alloy has been carried out in two different ways: the first way is based on the measurements of saturation magnetization under variable mechanical stress and the second one is founded on the quantitative theoretical treatment of experimental stress–strain loops. A functional dependence between the volume fraction of transformed martensite and applied stress has been determined from both magnetization and strain values. A quantitative agreement between the functions determined in two different ways has been observed, and hence, the effectiveness of the magnetic indication of the stress-induced martensitic transformations has been proved. This method can be used to monitor stress-induced transformations in martensitic films, needles and small specimens.     

A fabrication technology for epitaxial Ni-Mn-Ga microactuators

This paper reports on the fabrication and characterization of epitaxial Ni-Mn-Ga microactuators. Ni-Mn-Ga films are grown on heated single-crystalline MgO substrates by DC magnetron sputtering. X-ray diffraction measurements demonstrate epitaxial growth of the films. At room temperature, the crystal structure is identified to be non-modulated (NM) tetragonal martensite. Electrical resistance measurements confirm that the films display the martensitic phase transformation well above the Curie temperature T_C of 325 K. Orientation-dependent magnetization measurements are performed to determine magnetic film properties. Micromachining of the Ni-Mn-Ga films is performed on an alumina substrate covered by a temporary adhesive layer. A transfer bonding process is developed to finally integrate the micromachined Ni-Mn-Ga structures to a target substrate in order to obtain NiMnGa microactuators having freely movable microparts. Temperature-displacement characteristics demonstrate the actuation performance of epitaxial NiMnGa microactuators for the first time.     

Pulsed laser deposition of NiMnGa thin films on silicon

Thin films of the magnetic shape-memory (MSM) material NiMnGa have been deposited on Si(100) substrates using pulsed laser deposition. The -–200 300nm-thick films were prepared at substrate temperatures ranging from 450 °C to 650 °C and at different background Ar pressures. Large saturation magnetizations, up to 60% of the bulk value, were measured for the films. Only the films deposited in vacuum or at Ar pressures below 10^-3 mbar and at temperatures between 500 °C and 600 °C were ferromagnetic. The films are mainly crystallized in the austenitic phase and they have a smooth surface with a low droplet density (0.01 m^-2). The magnetization and surface quality are sufficient that the films could be utilized in the realization of thin-film MSM devices. PACS 75.70.Ak