TY  - JOUR
AU  - Jánossy, András
AU  - Brunel, LC
AU  - Cooper, Jr
TI  - Gd3+ ESR determination of the local spin susceptibility in Gd:YBa2Cu3Oy high-temperature superconductors
JF  - PHYSICAL REVIEW B
J2  - PHYS REV B
VL  - 54
PY  - 1996
IS  - 14
SP  - 10186
EP  - 10191
PG  - 6
SN  - 2469-9950
DO  - 10.1103/PhysRevB.54.10186
UR  - https://m2.mtmt.hu/api/publication/2609332
ID  - 2609332
AB  - Gd3+ ESR at high fields in Gd-doped high-T-c superconductors is shown to be a precise probe of the conduction electron static spin susceptibility, chi. The Gd3+ ESR Knight shift at 245 GHz and the spin relaxation broadening at 245 and 9.2 GHz in Gd0.01Y0.99Ba2Cu3Oy (with various values of between 6.05 and 7.0) are in agreement with published Y-89 NMR data above 70 K and provide additional measurements at the rare earth site at much lower temperatures. In the superconducting compounds chi(T) differs strongly from the Yoshida function and at low T it follows a T or T-2 dependence. An anomalous ESR line shape is found at low T in the superconducting state; we provisionally attribute this to a small (10(-2)-10(-3) mu(B)) static magnetic moment on planar Cu sites.
LA  - English
DB  - MTMT
ER  - 

TY  - JOUR
AU  - Rockenbauer, Antal
AU  - Jánossy, András
AU  - Korecz, László
AU  - Pekker, Sándor
TI  - Electron paramagnetic resonance spectroscopy of Gd-doped YBa2CU3O6+y crystallites aligned in a magnetic field
JF  - JOURNAL OF MAGNETIC RESONANCE
J2  - J MAGN RESON
VL  - 97
PY  - 1992
IS  - 3
SP  - 540
EP  - 552
PG  - 13
SN  - 1090-7807
DO  - 10.1016/0022-2364(92)90034-5
UR  - https://m2.mtmt.hu/api/publication/2538786
ID  - 2538786
AB  - Gd EPR spectra of Y0.999Gd0.001Ba2Cu3O6+y (0 ≤ y ≤ 1.) crystallites aligned in a magnetic field are investigated with field parallel to the c crystalline axis. For low oxygen contents (y ≤ 0.1) no spectral change is observed, while for larger oxygen contents all major bands except the central peak split into a pattern of five subbands with y-dependent relative intensities. The five sets of subbands are assigned to oxygen configurations with zero, one, two, three, or four occupied positions in the Cu (1) Oy planes closest to the Gd atom. The spectroscopic parameters g, h2 0, b4 0, b6 0, b4 4, and b6 4 determined by an iteration procedure reconstruct well the positions of all allowed and forbidden transitions. Each subsequent oxygen coordination increases b2 2 by the same amount; this shows that the zero-field splitting depends linearly on the crystal field. © 1992.
LA  - English
DB  - MTMT
ER  - 

TY  - JOUR
AU  - Pekker, Sándor
AU  - Jánossy, András
AU  - Rockenbauer, Antal
TI  - Ordering of oxygen into chains and distribution of hole density in YBa2Cu3O1+x
JF  - PHYSICA C - SUPERCONDUCTIVITY AND ITS APPLICATIONS
J2  - PHYSICA C
VL  - 181
PY  - 1991
IS  - 1-3
SP  - 11
EP  - 17
PG  - 7
SN  - 0921-4534
DO  - 10.1016/0921-4534(91)90328-V
UR  - https://m2.mtmt.hu/api/publication/1478442
ID  - 1478442
AB  - A series of Y0.999Gd0.001Ba2Cu3O6+x compounds is studied by Gd3+ EPR in the full range of oxygen content. The fine structu re is modified by the hole distribution in the Cu(2)O2 layers mirroring oxygen chains in the Cu(1)Ox layers. The fine structure of 5 differently occupied first-neighbour Cu(1)Ox oxygen chain configurations surrounding the Gd3+ ions is resolved. Formation of chain begins at a threshold oxygen content x0=0.14. For x>0.14 oxygen in Cu(1)Ox planes is ordered mainly into chains, the amount of disordered oxygen decreases with increasing x. The EPR intensities are in quantitative agreement with a model calculation of 2-dimensionally ordered oxygen chains. © 1991.
LA  - English
DB  - MTMT
ER  - 

TY  - JOUR
AU  - Jánossy, András
AU  - Rockenbauer, Antal
AU  - Pekker, Sándor
TI  - Gd3+ electron paramagnetic resonance in the quasi-two-dimensional antiferromagnet YBa2Cu3O6.02:Gd
JF  - PHYSICA C - SUPERCONDUCTIVITY AND ITS APPLICATIONS
J2  - PHYSICA C
VL  - 167
PY  - 1990
IS  - 3-4
SP  - 301
EP  - 306
PG  - 6
SN  - 0921-4534
DO  - 10.1016/0921-4534(90)90346-G
UR  - https://m2.mtmt.hu/api/publication/1478444
ID  - 1478444
AB  - Electron paramagnetic resonance (EPR) at 9.25 GHz of Y1-xGdxBa2Cu3O6.02 (0.001 < x < 0.05) powder magnetically a ligned along the crystallographic c-direction shows a well resolved Gd3+ fine structure. The crystalline field parameters are determined and their temperature dependence discussed. Due to the special symmetry the exchange interaction between Gd3+ and antiferromagnetic CuO2 layers is small, contrary to Y2-uGduBaCuO5 where Gd3+ and Cu2+ magnetizations are strongly coupled. EPP serves as a probe for internal fields HI at the Gd sites; in Y0.99Gd0.01Ba2Cu2.97Fe0.03O6.02HI<15 G despite the Fe-induced magnetic transition. © 1990.
LA  - English
DB  - MTMT
ER  -