ISSN:
0392-6737
Keywords:
Response to electromagnetic fields
;
nuclear magnetic resonance
;
ultrasonic attenuation
;
Conference proceedings
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Summary 139La NQR spectra, μSR precessional frequencies and NQR relaxation ratesW driven by the Cu2+ spin fluctuations are used to study the static magnetic properties and the low-energy spin excitations upon substitution of Zn2+ (S=0) for Cu2+ (S=1/2) in the antiferromagnetic (AF) phases of La2 Cu1−x Zn x O4. It is found that the Neel temperaturesT N decrease withx almost linearly, with initial suppression rate close to 4, while the sublttice magnetization is only slightly affected, close to the behaviour expected for a 2DS=1/2 Heisenberg AF in the framework of dilution model. Also the spin wave spectrum appears slightly affected by Zn doping, with moderate effects possibly related to disorder in the AF interactions and/or to finite size. A novel and remarkable effect is observed forT≤100 K. The relaxation ratesW show large maxima, withx-dependentW max andT max. This phenomenon is attributed to the cooperative freezing of local magnetic moments induced by Zn on Cu orbitals. Information on the characteristic fluctuation frequencies and on the spin-glass state superimposed to the AF matrix are thus obtained.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02462175
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