Neutron Scattering Studies of La2_xBaxCuO4
| Autor: | Van, Gastel J. Gregory |
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| Rok vydání: | 2011 |
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| Druh dokumentu: | Diplomová práce |
| Popis: | Elastic neutron scattering studies have been performed on high quality single crystal samples of lightly doped La2_xBaxCuO4 with concent rations of x=0, 0.006, 0.0125 and 0.025. These samples display x dependent magnetic structures with transition temperatures which closely follow the usual phase diagram for this material. A low temperature, 2D antiferromagnetic transition has been observed in samples with hole concent ration near the 'spin-glass' transition at x~0.02. In data collected on the N5 triple axis spectrometer at Chalk River, the sample with x=0.0125 demonstrates the onset of 3D antiferromagnetism with TN ~ 151K, followed by attenuation of the scattering intensity of the (1/2,1/2,0) magnetic Bragg peak below T=21K, indicating the onset of 2D magnetic ordering. This result is similar to that obtained by Matsuda et al. in lightly doped La2_xSrxCuO4.[1] This result is confirmed by direct observations of 2D 'rods ' of magnetic scattering in time-of-flight measurements performed on the Disk Chopper Spectrometer at NIST. Master of Science (MS) |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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