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Nuclear Data Sheets for A = 139

The experimental nuclear spectroscopic data for known nuclides of mass number 139 (Sn, Sb, Te, I, Xe, Cs, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy) have been evaluated and presented together with adopted properties for levels and gamma rays. This evaluation represents a revision of previous one (2001Bu16) by T.W. Burrows. Since then extensive new data have become available for many A=139 nuclides although, no excited state data are yet available for {sup 139}Sn, {sup 139}Sb, {sup 139}Tb, and {sup 139}Dy. The decay schemes of {sup 139}Sn, {sup 139}Sb, {sup 139}I, {sup 139}Tb and {sup 139}Dy nuclei are not known, and those for {sup 139}Gd and {sup 139}Eu are poorly known. Particle-transfer data are available for {sup 139}Ba, {sup 139}La, {sup 139}Ce and {sup 139}Pr. Limited high-spin data are available for {sup 139}Te, {sup 139}I, {sup 139}Cs, {sup 139}Ba, {sup 139}La and {sup 139}Ce, while such data are extensive for {sup 139}Pr, {sup 139}Nd, {sup 139}Pm, {sup 139}Sm, {sup 139}Eu and {sup 139}Gd. Recent {sup 139}Pm high-spin data from two independent studies using the same reaction and similar beam energy are in conflict and could be improved using state-of-the-art large gamma-detector arrays in contrast to the smaller arrays currently used. Cases for which no new experimental information are available since the last update have undergone checking resulting in some changes in the current work, but for the most part these are taken from the previous evaluations. Thus, the present work has greatly benefited from all prior NDS evaluations (2001Bu16, 1989Bu12, 1981Pe04, 1974Gr46), but at the same time data presented herein supersede those in the earlier evaluations.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Magnetic and transport properties of nanocrystalline double perovskite Sm{sub 2}CoMnO{sub 6}

Double perovskite Sm{sub 2}CoMnO{sub 6} nanoparticles of diameter around 200 nm were synthesized by a sol-gel technique. They showed ferromagnetic transition with a Curie temperature of 139 K. The saturation magnetization per formula unit (3.74 μ{sub B}/f.u.) as derived from magnetization-field data at 2 K was smaller than the theoretical value 6 μ{sub B}/f.u.. This was ascribed to the presence of antisite disorder. The resistivity was found to be controlled by a variable range hopping mechanism. The material exhibited negative magnetoresistance with a maximum value of 3% at 170 K for an applied field of 5 T. This was ascribed to spin-polarized electron hopping between magnetic domains coupled by an antiferromagnetic interaction.

77 NANOSCIENCE AND NANOTECHNOLOGY↗