Structure and Magnetic Properties of

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Structure and Magnetic Properties of

(Ru

_1−y

Nb

_y

)Sr

₂

(Nd

_0.67

Tb

_0.67

Ce

_0.66

)Cu

₂

O

_z

: Effect of Nb and Tb Substitutions

H. K. Lee^∗ · G. W. Kim

Department of Physics, Kangwon National University, Chuncheon 200-701, Korea (Received 1 August 2014 : revised 4 August 2014 : accepted 4 August 2014)

Polycrystalline samples of (Ru0.9Nb0.1)Sr2(Nd 1−x/2Tb1−x/2Cex)Cu2Oz (0.5 ≤ x ≤ 1.0) and (Ru1−yNby)Sr2(Nd0.67Tb0.67Ce0.66)Cu2Oz (0 ≤ y ≤ 1.0) were synthesized by using a solid-state reaction method. The structure and the magnetic properties were investigated by means of X-ray diffraction (XRD) and magnetization measurements. XRD data revealed that almost single-phase samples could be obtained for x = 0.66 - 0.8. Nb substitution was also found to result in a reduction of the weak-ferromagnetic component of the field-cooled (FC) magnetization and a reduction in the magnetic-ordering temperature. Based on the results of a Rietveld refinement of the XRD data, we discuss the structure and the magnetic behaviors induced by Nb doping and the local structural changes in the Ru sublattice.

PACS numbers: 74.72.-h, 74.72.Jt, 74.62.Bf, 74.25.Ha

Keywords: (Ru,Nb)Sr2(Nd,Tb,Ce)Cu2Oz, Nb doping, Structure, Magnetic property

Nb õ m Í TbV ò & ÿ; c Â \ ¥ (Ru

^1−y

Nb

_y

)Sr

₂

(Nd

_0.67

Tb

_0.67

Ce

_0.66

)Cu

₂

O

_z

4 8 ý º õ m Í

M X ì Ä ¤V R Ë

T

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y©

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(2014¸ 8Z4 1{9 ~ÃÎ6£§, 2014¸ 8Z4 4{9 Ãº&ñ:r~ÃÎ6£§, 2014¸ 8Z4 4{9 >FSX&ñ)

(Ru0.9Nb0.1)Sr2(Nd1−x/2Tb1−x/2Cex)Cu2Oz (0.5 ≤ x ≤ 1.0)õ (Ru1−yNby)Sr2(Nd0.67Tb0.67

Ce0.66)Cu2Oz (0 ≤ y ≤ 1.0)¸$í_ &ñ r¼#`¦ ¦© ìøÍ6£xZOÜ¼Ð ½+Ë$í ¦ Õª ½¨¸ü< l&h :

£¤$í`¦ X- r]X (XRD) x9 o¸ :£¤$í 8£¤&ñ`¦ :xK ½¨Ùþ¡. XRD ìr$3 õH x = 0.66 - 0.8 {9 M

: _ éß{9© r¼#s ½+Ë$íHd`¦Ð# ÅÒ%3. ¢¸ôÇ Nb_ u¨8|¾Ós 7£x÷& ls :r¸ ÷rm

field-cooled (FC) 8£¤&ñZOÜ¼Ð 8£¤&ñ)a ôÇ y©$í $íìr_ ß¼l¸ yèHds'a8£¤÷&%3. Nb u¨8 Ü

¼Ð l)a ½¨¸ x9 l&h :£¤$í\¦ XRDX<s'_ Rietveld ìr$3Ü¼Ð %3#Q Ru ÅÒ0A_ ²DGè½¨¸

oü< > # 7H_÷&%3.

PACS numbers: 74.72.-h, 74.72.Jf, 74.62.Bf, 74.25.Ha

Keywords:(Ru,Nb)Sr2(Nd,Tb,Ce)Cu2Oz, Nb¸iç, ½¨¸, l&h :£¤$í

∗E-mail: [email protected]

952

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Fig. 1. XRD patterns for (Ru0.9Nb0.1)Sr2(Nd_1−x/2 Tb_1−x/2Cex)Cu2Oz(0.5 ≤ x ≤ 1.0) samples. Peaks due to impurity phases are denoted by asterisk.

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Structure and Magnetic Properties of