Magnetic structure and ordering of Nd ions in Ga substituted NdBa{sub 2}Cu{sub 3}O{sub 7} (abstract)
- Max-Planck-Institut fuer Festkoerperforschung, 70569 Stuttgart (Germany)
- Laboratory for Neutron Scattering, ETH Zuerich
- Insitut-Laue-Langevin, Grenoble Cedex 9 (France)
Magnetic ordering of Nd{sup 3+} ion changes with oxygen concentration in NdBa{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}}. In the oxygen-rich sample NdBa{sub 2}Cu{sub 3}O{sub 6.9}, Nd{sup 3+} ion orders antiferromagnetically with 2D-Ising type of ordering. Whereas, in the oxygen reduced compound NdBa{sub 2}Cu{sub 3}O{sub 6.2} Nd ion orders three dimensionally at 1.73 K. Similar effects has been observed by specific heat measurements performed on NdBa{sub 2}Cu{sub 3{minus}{ital y}}Ga{sub {ital y}}O{sub 7} (0{lt}{ital y}{lt}0.5). In these samples, a small amount of Ga substitution changes the magnetic ordering of Nd ions from 2D Ising ({ital y}=0) to 1D or magnetic clusters ({ital y}=0.01, 0.03). With higher Ga substitution, the third magnetic ordering is restored. The magnetic ordering seen in NdBa{sub 2}Cu{sub 3{minus}{ital y}}Ga{sub {ital y}}O{sub 7} ({ital y}=0.5) is more isotropic in nature compared to NdBa{sub 2}Cu{sub 3}O{sub 6.2}. The critical exponent derived from the specific data show a 3D spherical type of ordering. Magnetic neutron diffraction are performed at low and high temperatures for {ital y}=0.5 to deduce the magnetic structure, which are compared with the unsubstituted compounds and to verify the isotropic nature. The second-order CEF parameter {ital A}{sup 0}{sub 2} decreases for NdBa{sub 2}Cu{sub 3{minus}{ital y}}Ga{sub {ital y}}O{sub 7} ({ital y}=0.5) which in turn reduces the magnetic anisotropy constant, consistent with magnetic specific heat results. {copyright} {ital 1996 American Institute of Physics.}
- OSTI ID:
- 280075
- Report Number(s):
- CONF-951101--
- Journal Information:
- Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 8 Vol. 79; ISSN JAPIAU; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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