Spin-wave excitations in ribbon-shaped Fe nanoparticles

It has been found that in highly anisometric ribbon-shaped Fe particles with nanoscale dimensions that the magnetization decreases with temperature markedly faster than in bulk bcc Fe. This anomalous dependence, which becomes more remarkable as the length-to-cross section ratio increases, arises from the elongated shape of the particles. The analytical approximation performed on the thermal spectrum of magnons, compatible with the sample dimensions, unravels the correlated influences of shape and size on the thermal decreasing rate of magnetization

Precise Thermal NDE for Quantifying Structural Damage

We have developed precise thermal NDE as a wide-area inspection tool to quantify structural damage within airframes and bridge decks. We used infrared cameras and image processing to produce precise temperature, thermal inertia, and cooling-rate maps of flash-heated aircraft skins. These maps allowed us to distinguish major structural defects from minor flaws which do not warrant costly repairs. We quantified aircraft skin corrosion defects with metal losses as low as 5% with 3% overall uncertainty [1–6]. We proved the feasibility of precise thermal NDE to inspect naturally-heated asphalt-concrete bridge decks. To this end, we quantified structural damage within asphalt-concrete slabs by locating the sites, and determining the relative volumes, of concrete displacements from 2-inch deep and 4-inch deep synthetic delaminations in asphalt-concrete slabs [4–8]

Mechanically driven alloying of immiscible elements (Comment)

In conclusion we have proven that the fact that both fcc FeCu and bcc Fe magnetization agree at 300 K is simply an accident and our data at low temperature show clearly that the Fe contribution after precipitation from the metastable phase has a deficiency in magnetization of at least 20% with respect to the Fe state in fcc FeCu metastable solid solution

Thermoremanence anomaly in Fe-Zr(B,Cu) Invar metallic glasses: Volume expansion induced ferromagnetism

We report the existence of a thermally induced sharp increase of thermoremanence around the Curie temperature of Invar-like Fe-Zr(B,Cu) soft magnetic glasses. Neutron-diffraction measurements indicate that a true enhancement of the average local magnetic moment, rather than only a change in the domain structure, occurs. Such enhancement has been tentatively attributed to the increasing volume expansion that takes place beyond the Curie temperature and reinforces ferromagnetism in some low-density clusters

Field and temperature dependence of magnetization in FeCu-based amorphous alloys

In this paper, the production of FeCu-based FeCuZr amorphous alloys by ball milling is reported. The thermal dependence of magnetization for the [Fe_(0.5)Cu_(0.5)]_85Zr_(15) (at. %) amorphous alloy has been found to show a dramatic field dependence of the kink point of the magnetization. This kink corresponds to a temperature different from the Curie temperature, above 400 K, of the ferromagnetic phase, which, according to spin waves fitting, can be induced by applying external fields. Just above 235 K, the thermoremanence increases sharply, and this feature strongly suggests an increase of the ferromagnetic ordering under zero field heating. Neutron diffraction experiments seem to confirm the enhancement of spin alignment. The thermal expansion above the compensation temperature is proposed to be the origin of the thermoremanence enhancement through the anti-Invar effect as might be explained within the framework of recent ab initio calculations [M. van Schilfgaarde et al., Nature (London) 400, 46 (1999)]

Correlation of dynamic contrast-enhanced bone perfusion with morphologic ultra-short echo time MR imaging in medication-related osteonecrosis of the jaw

OBJECTIVES: To investigate whether dynamic contrast-enhanced (DCE)-MR bone perfusion could serve as surrogate for morphologic ultra-short echo time (UTE) bone images and to correlate perfusion with morphologic hallmarks in histologically proven foci of medication-related osteonecrosis of the jaw (MRONJ). METHODS: Retrospective study including 20 patients with established diagnosis of MRONJ. Qualitative consensus assessment of predefined jaw regions by two radiologists was used as reference standard using Likert scale (0-3) for standard imaging hallmarks in MRONJ (osteolysis, sclerosis, periosteal thickening). DCE-MRI measurements performed in corresponding regions of the mandible were then correlated with qualitative scores. Regions were grouped into "non-affected" and "pathologic" based on binarized Likert scores of different imaging hallmarks (0-1 vs 2-3). DCE-MRI measurements among hallmarks were compared using Mann-Whitney-U-testing. ROC (receiver-operating-characteristic) analysis was performed for each of the perfusion parameters to assess diagnostic performance for identification of MRONJ using morphologic ratings as reference standard. RESULTS: Median perfusion measurements of "pathologic" regions in wash-in, peak enhancement intensity and integrated area under the curve are significantly higher than those of "non-affected" regions, irrespective of reference imaging hallmark (p < 0.05). No significant perfusion differences were found between "pathologic" regions with and without osteolysis (p = 0.180). ROC analysis showed fair diagnostic performance of DCE-MRI parameters for identification of MRONJ (AUC 0.626-0.727). CONCLUSIONS: DCE bone perfusion parameters are significantly increased in MRONJ compared to non-affected regions, irrespective of osteolysis. Due to certain overlap DCE-MRI bone perfusion cannot serve as full surrogate for UTE bone imaging but may enhance reader confidence

Search for Deeply Bound Kaonic Nuclear States with AMADEUS

We briefly report on the search for Deeply Bound Kaonic Nuclear States with AMADEUS in the Sigma0 p channel following K- absorption on 12C and outline future perspectives for this work

Magnetic-properties of Cu-doped porous silica-gels - a possible Cu ferromagnet

We have studied the magnetic properties of Cu-doped porous silica gels and found that the system seems to be ferromagnetic up to room temperature. This result is fascinating because the amount of Cu ranges from 0.15% to 3% in weight of the total sample. Magnetization, hysteresis loops, and EPR experiments are presented. The paramagnetic signal of the silica gel without doping is negligible. On the other hand, the analysis of the magnetic impurities by x-ray fluorescence shows that these impurities can account for only 10% of the magnetization observed at 300 K

Ferromagnetism in fcc twinned 2.4 nm size Pd nanoparticles

The onset of ferromagnetism has been experimentally observed in small Pd particles of average diameter 2.4 nm. High-resolution studies reveal that a high percentage of the fcc particle exhibits single and multiple twinning boundaries. The spontaneous magnetization close to 0.02 emu/g seems to indicate that only a small fraction of atoms holds a permanent magnetic moment and contributes to ferromagnetism. The possible origin of ferromagnetism is briefly discussed according to different models recently reported