TY - JOUR
T1 - The effect of Ca and Th substitution on the crystal-field spectrum of the high-Tc superconductor HoBa2Cu3Ox
AU - Golosova, N.
AU - Podlesnyak, A.
AU - Mitberg, E.
AU - Bobrovskii, V.
AU - Mirmelstein, A.
AU - Furrer, A.
PY - 2002/3/4
Y1 - 2002/3/4
N2 - The inelastic neutron scattering technique was employed to study the transitions between the low-lying levels of the ground-state J-multiplet of the Ho3+ ions in Ho1-yCayBa2Cu3Ox (x ≈ 6.3, 7.0; y ≈ 0.1, 0.2) and Ho1-yThyBa2Cu3Ox (x ≈ 6.3; y ≈ 0.07, 0.13) split by the crystalline electric field. For oxygen-rich Ca-doped samples, the observed energy spectra exhibit a fine structure, which reflects the behaviour of the local hole density near the doping centre. For the first time this experimental observation unambiguously confirms that the charge inhomogeneity, which was found to be a characteristic feature of the underdoped cuprates, still exists in the deeply overdoped regime with Tc = 56 K. On the other hand, the modification of the crystal-field spectra observed for the oxygen-deficient samples with both Ca2+ and Th4+ substitutions for Ho3+ is found to result from distortions of the copper-oxygen polyhedron around the Ho3+ ion in the direct neighbourhood of the implanted ions, rather than from the doping-induced variation of the carrier concentration in the CuO2 planes.
AB - The inelastic neutron scattering technique was employed to study the transitions between the low-lying levels of the ground-state J-multiplet of the Ho3+ ions in Ho1-yCayBa2Cu3Ox (x ≈ 6.3, 7.0; y ≈ 0.1, 0.2) and Ho1-yThyBa2Cu3Ox (x ≈ 6.3; y ≈ 0.07, 0.13) split by the crystalline electric field. For oxygen-rich Ca-doped samples, the observed energy spectra exhibit a fine structure, which reflects the behaviour of the local hole density near the doping centre. For the first time this experimental observation unambiguously confirms that the charge inhomogeneity, which was found to be a characteristic feature of the underdoped cuprates, still exists in the deeply overdoped regime with Tc = 56 K. On the other hand, the modification of the crystal-field spectra observed for the oxygen-deficient samples with both Ca2+ and Th4+ substitutions for Ho3+ is found to result from distortions of the copper-oxygen polyhedron around the Ho3+ ion in the direct neighbourhood of the implanted ions, rather than from the doping-induced variation of the carrier concentration in the CuO2 planes.
UR - http://www.scopus.com/inward/record.url?scp=0037017592&partnerID=8YFLogxK
U2 - 10.1088/0953-8984/14/8/320
DO - 10.1088/0953-8984/14/8/320
M3 - Article
AN - SCOPUS:0037017592
SN - 0953-8984
VL - 14
SP - 1923
EP - 1936
JO - Journal of Physics Condensed Matter
JF - Journal of Physics Condensed Matter
IS - 8
ER -