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1Author    B.V S Murthy, K. P. Ramesh, J. RamakrishnaRequires cookie*
 Title    Molecular Dynamics in Tetramethyl Ammonium Hexabromo Selenate [N(CH 3 ) 4 ] 2 SeBr 6 . A Proton NMR Study  
 Abstract    spin-lattice relaxation time Ti and second moment M 2 have been studied as a function of tem-perature over the temperature range 445 to 77 K. A discontinuous change in Ti at 365 K, in-dicates the presence of a phase transition, while the slope change at 152 K, is attributed to a change in the TMA ion dynamics from tumbling to torsion. The 7i results could be explained in terms of inequivalent TMA ions and their small angle torsional oscillations. A second moment (M 2) transition occurs around 160 K and is ascribed to the freezing of TMA tumbling and CH 3 reorientation. 
  Reference    Z. Naturforsch. 48a, 868—870 (1993); received February 22 1993 
  Published    1993 
  Keywords    Molecular dynamics, Second moment, NMR, Spin-lattice relaxation time 
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 TEI-XML for    default:Reihe_A/48/ZNA-1993-48a-0868.pdf 
 Identifier    ZNA-1993-48a-0868 
 Volume    48 
2Author    Yasumasa Tomita, Koji Yamada, Hiroshi Ohki, Tsutomu OkudaRequires cookie*
 Title    Structure and Dynamics of Li 3 InBr 6 and NaInBr 4 by Means of Nuclear Magnetic Resonance  
 Abstract    Li 3 InBr 6 and NaInBr 4 have been synthesized and characterized by means of DTA, 8 'Br NQR, 6 Li, 7 Li, 23 Na, and ll5 In NMR, and AC conductivity. These measurements revealed the presence of phase transitions and cationic diffusion in both compounds. From the spin-lattice relaxation times of 1 Br NQR and the peak widths of 7 Li and 23 Na NMR spectra, it is deduced that the conduction is due to cat-ionic diffusion. The activity energy for the Li + diffusion was found to be 24 kJ/mol for Li 3 InBr 6 . 
  Reference    Z. Naturforsch. 53a, 466—472 (1998); received January 26 1998 
  Published    1998 
  Keywords    NQR, NMR, Spin-lattice Relaxation Time, AC Conductivity, Cation Diffusion 
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 TEI-XML for    default:Reihe_A/53/ZNA-1998-53a-0466.pdf 
 Identifier    ZNA-1998-53a-0466 
 Volume    53 
3Author    M. R., R., Haruo Niki, Shoichi Tomiyoshi, Takeshi Shinohara, Mamoru Omori, Tsuyoshi Kajitani, Hiroshi Kyan, Takeshi Hamagawa, Hirotaka Odahara, N.M R Proton, M. R.Requires cookie*
 Title    Hydrogen-doped Antiferromagnetic YBa2Cu30 7_ 5H x as Studied by Proton N  
 Abstract    of the C u(l) site have been measured on the antiferromagnetic phase of a powdered sample of hydrogen-doped tetragonal YBa2C u30 6 jHq 14 between 5 and 300 K. The line width, Aa>, of *H N M R increases abruptly below 20 K. The enhancement of T2_1 and that of Tj-1 of 63Cu (1) N Q R occurs around 20 K and 40 K, respectively. The nuclear magnetization does not recover in a simple exponential manner below 80 K. The predominant mechanism governing Tx below 80 K was found to be the fluctuating magnetic field which originates from the staggered C u2 + moments in either the C u(l) oxygen-deficient layer or the C u(2)02 plane induced by the hole doping effect. These enhancements and the abrupt increase in Aco are attributed to this fluctuating magnetic field. 
  Reference    Z. Naturforsch. 49a, 401—406 (1994); received August 12 1993 
  Published    1994 
  Keywords    Antiferromagnetic materials, High-7^ superconductor, Spin-lattice relaxation time, Spin-spin relaxation time, Proton N 
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 TEI-XML for    default:Reihe_A/49/ZNA-1994-49a-0401.pdf 
 Identifier    ZNA-1994-49a-0401 
 Volume    49 
4Author    Mineyuki Hattori, Yoshito Onoda, Tomoki Erata, M. E. Smith, Bruker Analytische, M. Esstechnik, G. M. Bh, Masakazu Hattori, Hiroshi Ohki, Ryuichi IkedaRequires cookie*
 Title    Ionic motion and Disordered Structure in the Rotator Phase of Butylammonium Chloride Studied by Temperature Dependences of 35C1 and 2HNMR  
 Abstract    Temperature dependences o f 35C1 and 2H quadrupole coupling constants and 35C1 N M R spin-lat­ tice relaxation times in polycrystalline samples were measured in the rotator phase of the butylam ­ m onium chlorides C 4H 9N H 3C1 and C4H 9N D 3C1, obtainable above the phase transition tempera­ ture o f 241 K. A rapid decrease o f the quadrupole coupling constants of both nuclei upon heating is attributed to increasing dynam ic disorder formed around the polar head. The presence of self-dif-fussion o f C P ions was revealed from the spin-spin relaxation time and resonance line-width in single crystals, and confirmed by measuring the dc electrical conductivity. 
  Reference    Z. Naturforsch. 49a, 291 (1994); received July 23 1993 
  Published    1994 
  Keywords    Solid N M R, Quadrupole coupling constant, Spin-lattice relaxation time, Self-diffusion, Rotator phase 
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 TEI-XML for    default:Reihe_A/49/ZNA-1994-49a-0291.pdf 
 Identifier    ZNA-1994-49a-0291 
 Volume    49 
5Author    Haruo Niki, Kikuhiro Kano, Mitsuhiro Takase, Kensei Majikina, Katsuma Yagasaki, Takeshi Shinohara, Mamoru Omori, Shoichi Tomiyoshi, Etsuo AkibaRequires cookie*
 Title    Oxygen Content Dependence of 63 Cu(l) NQR and Proton NMR in Hydrogen-Doped Antiferromagnetic YBa 2 Cu 3 0 6+A: H y  
 Abstract    The oxygen content dependence of 63 Cu NQR at the Cu(l) site and proton NMR have been meas-ured in the antiferromagnetic phase of powdered samples of hydrogen-doped YBa 2 Cu 3 0 6+x .H v (0.07 < JC < 0.17 and y » 1) from 4.2 to 90 K. The spectrum of 1 H NMR is a single line and the line width increases below 15 Kdue to magnetic interactions. The enhancements of Tf 1 and 7^ 1 of 63 Cu(l)NQR occur around 35 and 15 K, respectively. These enhancements increase with increasing oxygen concen-tration. The maximum values of Tf 1 and T^ for the sample with x = 0.17 reach 200 sec -1 and more than 7 msec -1 , respectively. The predominant source for the relaxation mechanism of 63 Cu(l) NQR and the line broadening of 'H NMR are found to be the fluctuating magnetic field due to the staggered Cu 2+ moments. 
  Reference    Z. Naturforsch. 53a, 518—523 (1998); received March 24 1998 
  Published    1998 
  Keywords    Antiferromagnetic materials, High-T^ superconductor, Spin-lattice Relaxation Time, Cu NQR, Proton NMR 
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 TEI-XML for    default:Reihe_A/53/ZNA-1998-53a-0518.pdf 
 Identifier    ZNA-1998-53a-0518 
 Volume    53 
6Author    K. P. Ramesh, J. Ramakrishna, K. S. Suresh, C.Raghavendra RaoRequires cookie*
 Title    Pressure Dependence of the Chlorine NQR in Chloro Pyridines  
 Abstract    The "CI NQR frequency (VQ) and spin lattice relaxation time) in 2,6-dichloropyridine, 2 amino 3,5-dichloropyridine and 6 chloro 2-pyridinol have been measured as a function of pressure up to 5.1 kbar at 300 K, and the data have been analysed to estimate the temperature coefficients of the NQR frequency at constant volume. All the three compounds show a non linear variation of the NQR frequen-cy with pressure which can be described by a 2 nd order polynomial in pressure. The rate of change of the NQR frequency with pressure is positive and decreases with increasing pressure. The spin lattice re-laxation time 7, in all the three compounds shows a small increase with pressure, indicating that the re-laxation is mainly due to the torsional motions. 
  Reference    Z. Naturforsch. 55a, 111—116 (2000); received August 25 1999 
  Published    2000 
  Keywords    Chlorine NQR, Spin-Lattice Relaxation Time, Pressure Dependence, 2,6 dichloropyridine, 2-amino 3,5-dichloropyrine, 6-chloro 2-pyridinol 
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 TEI-XML for    default:Reihe_A/55/ZNA-2000-55a-0111.pdf 
 Identifier    ZNA-2000-55a-0111 
 Volume    55 
7Author    K. S. Suresh3, K. P. Rameshb, C. Raghavendra Rao3, J. RamakrishnabRequires cookie*
 Title    Pressure Dependence of the Chlorine NQR in Three Solid Chloro Anisoles  
 Abstract    The 35C1 Nuclear Quadrupole Resonance (NQR) frequency (V q) and spin lattice relaxation time (T{) in the three anisoles 2,3,4-trichloroanisole, 2,3,6-trichloroanisole and 3,5-dichloroanisole have been measured as a function of pressure upto 5.1 kbar at 300 K, and the data have been analysed to estimate the temperature coefficients of the NQR frequency at constant volume. All the three com­ pounds show a non linear variation of the NQR frequency with pressure, the rate of which is positive and decreases with increasing pressure. In case of 3,5-dichloroanisole the value becomes negative in the higher range of pressure studied. The spin lattice relaxation time T{ in all the three compounds shows a weak dependence on pressure, indicating that the relaxation is mainly due to the torsional motions. 
  Reference    Z. Naturforsch. 56a, 764—772 (2001); received July 19 2001 
  Published    2001 
  Keywords    NQR, 35C1, Frequency, Spin-lattice Relaxation Time, Torsional Motion, Pressure and Temperature Dependence, 3,5-dichloroanisole, 2,3,4-trichloroanisole, 2,3,6-trichloroan­ isole 
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 TEI-XML for    default:Reihe_A/56/ZNA-2001-56a-0764.pdf 
 Identifier    ZNA-2001-56a-0764 
 Volume    56