37 research outputs found
Site-Dilution-Induced Antiferromagnetic Long-Range Order in Two-Dimensional Spin-Gapped Heisenberg Antiferromagnet
Effects of the site dilution on spin-gapped Heisenberg antiferromagnets with
and S=1 on a square lattice are investigated by means of the quantum
Monte Carlo method. It is found that effective magnetic moments induced around
the diluted sites exhibit the antiferromagnetic long-range order in the medium
of spin-singlet pairs. Their microscopic structure is examined in detail and
important roles of the higher dimensionality than one on the phenomenon are
discussed.Comment: RevTeX, 4 pages, 6 figure
On the alpha activity of natural tungsten isotopes
The indication for the alpha decay of 180-W with a half-life
T1/2=1.1+0.8-0.4(stat)+-0.3(syst)x10^18 yr has been observed for the first time
with the help of the super-low background 116-CdWO_4 crystal scintillators. In
conservative approach the lower limit on half-life of 180-W has been
established as T1/2>0.7x10^18 yr at 90% C.L. Besides, new T1/2 bounds were set
for alpha decay of 182-W, 183-W, 184-W and 186-W at the level of 10^20 yr.Comment: 16 pages, 8 figures, accepted in Phys. Rev.