The Magnetic Properties of Selected Rare Earth Nitrides Grown by Pulsed Laser Deposition

<p>Gadolinium nitride (GdN) and samarium nitride (SmN) are grown by pulsed laser deposition on yttria stabilised zirconia substrates. Surface and structural characterisation shows that the thin films are epitaxial with crystallites of up to 30 nm in diameter and a very large in plane coherence length. A novel oxide layer is observed at the substrate-film interface, caused by oxygen in the substrate reacting with the deposited rare earth element. GdN is found to be ferromagnetic below 70 K with a saturation moment of 7 Bohr magneton per ion. The relationship between the crystal structure and the magnetisation is investigated using ferromagnetic resonance and a weak easy axis along the [111] azimuth is reported. Hall effect measurements show the carriers are electrons, present in concentrations of 1020/cm3. Magnetic measurements on SmN show the presence of metallic droplets, but correcting for these, the Curie temperature is found to be 30 K.We report on preliminary growths of europium nitride and show the valence of the Eu is 3+, solving an outstanding theoretical question.</p>

The Magnetic Properties of Selected Rare Earth Nitrides Grown by Pulsed Laser Deposition

<p>Gadolinium nitride (GdN) and samarium nitride (SmN) are grown by pulsed laser deposition on yttria stabilised zirconia substrates. Surface and structural characterisation shows that the thin films are epitaxial with crystallites of up to 30 nm in diameter and a very large in plane coherence length. A novel oxide layer is observed at the substrate-film interface, caused by oxygen in the substrate reacting with the deposited rare earth element. GdN is found to be ferromagnetic below 70 K with a saturation moment of 7 Bohr magneton per ion. The relationship between the crystal structure and the magnetisation is investigated using ferromagnetic resonance and a weak easy axis along the [111] azimuth is reported. Hall effect measurements show the carriers are electrons, present in concentrations of 1020/cm3. Magnetic measurements on SmN show the presence of metallic droplets, but correcting for these, the Curie temperature is found to be 30 K.We report on preliminary growths of europium nitride and show the valence of the Eu is 3+, solving an outstanding theoretical question.</p>

Formation of Metallic Droplets on the Surface of Indium Sulfide Films During Argon Plasma Treatment

Modification of indium sulfide (In2S3) film surface was performed by the treatment in high-density low-pressure inductively coupled argon plasma. The films with thickness of 500–800[Formula: see text]nm were fabricated on glass substrates by the thermal evaporation method and subsequent annealing in sulfur ambience. The plasma treatment of as-grown and annealed films was carried out with argon ions having the energy of 25–200[Formula: see text]eV. Nanostructuring of the film surface took place resulting in the formation of arrays of nanosized indium droplets.

Analysis of Urnfield Period Bronze Droplets Formed during Casting

The Late Bronze Age copper mining site “Gasteil Cu I” (ca 1050–850 BC) is located in the district of Neunkirchen, Lower Austria. Since 2010 five excavation campaigns took place and many artifacts as well as corroded metallic droplets were discovered. Two of these droplets were investigated by metallography. At the droplet ́s surface tin was measured, indicating that these droplets are formed during bronze casting. The small droplet is severely corroded but in its core the original bronze alloy is still present. The analysis showed about 10 wt.% Sn. The microstructure is characterized by a Cu-Sn solid solution and a Cu-Sn intermetallic phase. Additionally small amounts of Cu2S were observed in the metallic core. The corroded rim contains oxides and hydroxides of Cu and Sn and other impurities like Ca, P, Si, S and Fe. Analyzing the corrosion products, Sn concentrations up to 40 wt.% were measured. This enrichment can be explained by a simultaneous formation of insoluble SnO2 and Cu ions, which were transported to the surface. Surprisingly, the other large droplet has a corroded core and metallic phases are remaining at the rim. The microstructures of the corrosion products reflect the original casting microstructures of the bronze.