Magnetic And Magnetocaloric Properties On The U1-y Ry Ga2 (r=er And Dy) Compound

The magnetic, calorimetric, and magnetocaloric properties of the pseudobinary U1-y Ry Ga2 (R=Er and Dy) series were studied to determine its potential as a candidate for use in cryogenic magnetic refrigeration. The partial substitution of Dy and Er for U provides a wide range of the ordering temperature and increases the saturation magnetic moment. The results for U1-y Dyy Ga2 with 0.6<y<0.9 show evidences of a spin-glass-like (SG) behavior, possibly as a consequence of competing anisotropy and exchange interactions within a frustrated hexagonal spin lattice. The isothermal magnetic entropy change (Δ Smag) observed for U Ga2 shows a well defined peak centered on TC, which is gradually broadened and shifted to lower temperatures as the Er and Dy content increases. For low concentrations (0.2≤y≤0.4) a tablelike profile is observed in the Δ Smag curve. © 2008 American Institute of Physics.1037Gschneidner Jr., K.A., Pecharsky, V.K., Tsokol, A.O., (2005) Radiat. Prot. Dosim., 68, p. 1479Bruck, E., (2005) J. Phys. D, 38, p. 381Yu, B.F., Gao, Q., Zhang, B., Meng, X.Z., Chen, Z., (2003) Int. J. Refrig., 26, p. 622Gschneidner Jr., K.A., Pecharsky, A.O., Pecharsky, V.K., (2001), 11, p. 433. , Cryoolers (Academic-Plenum, New York), Vol.,Smaili, A., Chahine, R., (1996) Adv. Cryog. Eng., 42, p. 445Hashimoto, T., Kuzuhura, T., Sahashi, M., Inomata, K., Tomokiyo, A., Yayama, H., (1987) J. Appl. Phys., 62, p. 3873Lima, A.L., Gschneidner Jr., K.A., Pecharsky, V.K., Pecharsky, A.O., (2003) Phys. Rev. B, 68, p. 134409De Oliveira, N.A., Von Ranke, P.J., (2003) J. Magn. Magn. Mater., 264, p. 55Tsai, T.H., Sellmyer, D.J., (1979) Phys. Rev. B, 20, p. 4577Doukouŕ, M., Gignoux, D., (1982) J. Magn. Magn. Mater., 30, p. 111Gignoux, D., Schimitt, D., Takeuchi, A., Zhang, F.Y., (1991) J. Magn. Magn. Mater., 97, p. 15Andreev, A.V., Belov, K.P., Deryagin, A.V., Levitin, R.Z., Menovsky, M., (1979) J. Phys. Colloq., 4, p. 82Mydosh, J.A., (1993), Spin Glasses: An Experimental Introduction (Taylor&Francis, London)Markin, P.E., Baranov, N.V., Sinitsyn, E.V., (1991) Physica B, 168, p. 19

Magnetocaloric Effect And Evidence Of Superparamagnetism In Gda L2 Nanocrystallites: A Magnetic-structural Correlation

The correlation between structural and magnetic properties of GdAl2, focusing on the role played by the disorder in magnetic ordering and how it influences the magnetocaloric effect (MCE) are discussed. Micrometric-sized particles, consisting of nanocrystallites embedded in an amorphous matrix, were prepared by a mechanical milling technique and characterized by means of x-ray diffraction, scanning and high-resolution transmission electron microscopy as well as magnetic measurements as a function of an applied external magnetic field and temperature. The results show that the average particle size is just slightly diminished (≈7%) with the milling time (between 3 and 13 h), whereas the average crystallite size undergoes an expressive reduction (≈43%). For long milling times, structural disorders mostly associated with crystallite size singularly affect the magnetic properties, leading to a large tablelike MCE in the temperature range between 30 and 165 K. Below 30 K, nanocrystallites with dimensions below a given critical size cause an enhancement in the magnetic entropy change related to superparamagnetic behavior. In contrast, for low milling times, relative cooling power values are improved. These striking features along with the small magnetic hysteresis observed make the milled GdAl2 a promising material for application in the magnetic refrigeration technology. Finally, a discussion in an attempt to elucidate the origin of the spin-glass states previously reported in the literature for mechanically milled GdAl2 samples for very long times (400 and 1000 h) is presented. © 2016 American Physical Society.93

Magnetization And Specific Heat In U 1-xla Xga 2 And Magnetocaloric Effect In Uga 2

We have investigated the properties of the ferromagnetic series U1-x Lax Ga2. The magnetization results show a reduction of μeff and of Tc when x is increased. The electronic coefficient γ of the specific heat increases to a maximum of 260 mJUmol K2 at x=0.75. This behavior is probably consequence of delocalization of 5f electrons, causing enhancement of the density of states. For x=0.9 the ordering disappears and a non-Fermi-liquid behavior is observed. U Ga2 also presented a significant magnetocaloric effect of Δ Smag =-3.5 Jkg K at 120 K and H=7 T which can be modified by chemical pressure. © 2005 American Institute of Physics.9710Andeev, A.V., Belov, K.P., Deriagin, A.V., Levitin, R.Z., Menovsky, A., (1979) J. Phys. Colloq., 4, p. 82Da Silva, L.M., Gandra, F.G., Rojas, D.P., Cardoso, L.P., Medina, A.N., (2002) Physica B, 312-313, p. 906Tran, V.H., Kaczorowski, D., Roisnel, T., Tróc, R., Noel, H., Bouŕe, F., Andŕ, G., (1995) Physica B, 205, p. 24Gandra, F.G., Rojas, D.P., Shlyk, L., Cardoso, L.P., Medina, A.N., (2001) J. Magn. Magn. Mater., 226, p. 1312Barbara, B., (1973) J. Phys. (Paris), 34, p. 1039Sechovsky, V., Havela, L., Svoboda, P., (1986) J. Less-Common Met., 121, p. 163Segal, E., Wallace, W.E., (1975) J. Solid State Chem., 13, p. 201Radwanski, R.J., Kim-Ngan, N.H., (1995) J. Magn. Magn. Mater., 140, p. 1373Zapf, V.S., Dickey, R.P., Freeman, E.J., Sirvent, C., Maple, M.B., (2002) Phys. Rev. B, 65, p. 024437Pecharsky, V.K., Gschneider Jr., K.A., (1997) Phys. Rev. Lett., 78, p. 4494Pecharsky, V.K., Gschneider Jr., K.A., (1997) Phys. Rev. Lett., 78, p. 4494Plackowski, T., Junod, A., Bouquet, F., Sheikin, I., Wang, Y., Jezÿowski, A., Mattenberger, K., (2003) Phys. Rev. B, 67, p. 184406Svobodaa, P., Sechovsky, V., Menovsky, A.A., (2003) Physica B, 339, p. 177Gama, S., Coelho, A.A., De Campos, A., Carvalho, A.M.G., Gandra, F.G., Von Ranke, P.J., De Oliveira, N.A., Phys. Rev. Lett

GWAS in Breast Cancer

Breast cancer is the most diagnosed cancer in women, and the second cause of cancer-related deaths among women worldwide. It is expected that more than 240,000 new cases and 40,450 deaths related to the disease will occur in 2016. It is well known that inherited genetic variants are drivers for breast cancer development. There are many mechanisms through which germline genetic variation affects prognosis, such as BRCA1 and BRCA2 genes, which account for approximately 20% of the increased hereditary risks. Therefore, it is evident that the genetic pathways that underlie cancer development are complex in which networks of multiple alleles confer disease susceptibility and risks. Global analyses through genome-wide association studies (GWAS) have revealed several loci across the genome are associated with the breast cancer. This chapter compiles all breast GWAS released since 2007, year of the first article published in this area, and discuss the future directions of this field. Currently, hundreds of genetic markers are linked to breast cancer, and understanding the underlying mechanisms of these variants might lead to the discover of biomarkers and targets for therapy in patients

Doped Semiconductor Nanocrystals: Development and Applications

This chapter aims to show significant progress that our group has been developing and the applications of several doped semiconductor nanocrystals (NCs), as nanopowders or embedded in glass systems. Depending on the type of dopant incorporated in the nanocrystals, the physical, chemical, and biological properties can be intensified. However, it can also generate undesired toxic effects that can potentially compromise its use. Here we present the potential of zinc oxide NCs doped with silver (Ag), gold (Au), and magnesium (Mg) ions to control bacterial diseases in agriculture. We have also performed biocompatibility analysis of the pure and Ag-doped sodium titanate (Na2Ti3O7) NCs in Drosophila. The doped nanocrystals embedded in glassy systems are chrome (Cr) or copper (Cu) in ZnTe and Bi2Te3 NCs for spintronic development nanodevices. Therefore, we will show several advantages that doped nanocrystals may present in the technological and biotechnological areas