Physics – Condensed Matter – Strongly Correlated Electrons
Scientific paper
2001-04-25
Physics
Condensed Matter
Strongly Correlated Electrons
13 pages with 14 figures, RevTex, accepted for publication in Phys. Rev. B
Scientific paper
10.1103/PhysRevB.65.094425
We have performed Electron Spin Resonance measurements on single crystals of the doped spin-Peierls compounds CuGe$_{1-y}$Si$_y$O$_3$ and Cu$_{1-x}$M$_x$GeO$_3$ with M = Zn, Mg, Ni ($x, y\leq 0.1$). The first part of our experiments was performed in the paramagnetic and spin-Peierls phases at 9.5, 95 and 190 GHz. All non-magnetic impurities (Si, Zn and Mg) were found to hardly affect the position and linewidth of the single line resonance, in spite of the moment formation due to the broken chains. In contrast to Si, Zn and Mg-doping, the presence of Ni (S = 1) at low concentration induces a spectacular shift towards high fields of the ESR line (up to 40% for x=0.002), together with a large broadening. This shift is strictly proportional to the ratio of Ni to Cu susceptibilities: Hence it is strongly enhanced below the spin-Peierls transition. We interpret this shift and the broadening as due to the exchange field induced by the Ni ions onto the strongly exchange coupled Cu spins. Second, the antiferromagnetic resonance was investigated in Ni-doped samples. The frequency vs magnetic field relation of the resonance is well explained by the classical theory with orthorhombic anisotropy, with $g$ values remarkably reduced, in accordance with the study of the spin-Peierls and paramagnetic phases. The easy, second-easy, and hard axes are found to be $a$, $c$, and $b$ axes, respectively. These results, which are dominated by the single ion anisotropy of Ni$^{2+}$, are discussed in comparison with those in the Zn- and Si-doped CuGeO$_3$.
Barra Anne Laure
Clément S.
Dhalenne Guy
Grenier Beatrice
Hagiwara Manabu
No associations
LandOfFree
Electron Spin Resonance of Ni-doped CuGeO$_3$ in the paramagnetic, spin-Peierls and antiferromagnetic states: Comparison with non-magnetic impurities does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Electron Spin Resonance of Ni-doped CuGeO$_3$ in the paramagnetic, spin-Peierls and antiferromagnetic states: Comparison with non-magnetic impurities, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electron Spin Resonance of Ni-doped CuGeO$_3$ in the paramagnetic, spin-Peierls and antiferromagnetic states: Comparison with non-magnetic impurities will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-647867