We studied local electronic states near Zn in optimally doped YBa2(Cu1−xZnx)3O 7−δ and underdoped YBa2(Cu1−xZnx)4O8 via satellite signals of plane-site Cu(2) nuclear quadrupole resonance (NQR) spectra. From the relative intensity of Cu NQR spectra, the satellite signals are assigned to Zn-neighbor Cu NQR lines. The Cu nuclear spinlattice relaxation time of the satellite signal is shorter than that of the main signal, which indicates that the magnetic correlation is locally enhanced near Zn both for the underdoped and the optimally doped systems. The pure YBa2Cu4O8 is a stoichiometric, homogenous, underdoped electronic system; nevertheless, the Zn-induced inhomogeneous magnetic response in the CuO2 plane is more marked than that of the optimally doped YBa2Cu3O 7−δ . 74.25.Nf, 74.72.Bk

Paleomagnetic investigation of Plio-Pleistocene formations in Sangiran and Mojokerto, Java was carried out to date stratigraphic levels of Pithecanthropus fossils. Secular variation records of paleomagnetic field direction from the two areas show very consistent changes with some prominent features. The record for the past 3 million years obtained in Sangiran revises the magnetostratigraphy of earlier investigations and reveals stratigraphic levels of polarity boundaries and events. Based on correlation of the secular variation record of Mojokerto with that of Sangiran, magnetostratigraphy of Pleistocene formations in Mojokerto was established. The stratigraphic zone of Pithecanthropus in Sangiran ranges from the lower boundary of Jaramillo event to the Brunhes/Matuyama boundary, and the stratigraphic level of Homo modjokertensis lies at the lower border of Jaramillo event. Magnetochronologically it dates from about 0.73-0.97m.y. for Sangiran and about 0.97m.y. for Mojokerto.

We studied low-frequency spin dynamics near the impurity-induced superconductor-to-insulator transition for underdoped high-T c superconductor YBa 2 (Cu 1-x M x ) 4 O 8 (M=Ni, Zn) using the Cu nuclear quadrupole resonance (NQR) spin-echo technique. We observed remarkable suppression of the normalstate pseudo spin-gap and a loss of Cu NQR spectrum intensity at low temperatures around the critical impurity concentration.

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