Structural, magnetic and electrical properties in the pyrochlore oxide Bi2−xCaxIr2O7−δ
Structural, magnetic and electrical properties in the pyrochlore oxide Bi2−xCaxIr2O7−δ
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DOI：
10.1016/j.ceramint.2015.11.149
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发表时间：
2016-02
影响因子：
5.2
通讯作者：
D. Liang;Hui Liu;Ning Liu;L. Ling;Yuyan Han;Lei Zhang;Changjin Zhang
中科院分区：
文献类型：
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作者：
D. Liang;Hui Liu;Ning Liu;L. Ling;Yuyan Han;Lei Zhang;Changjin Zhang
采用固相反应法在空气中合成了Bi 2 − xCaxIr 2 O 7 −δ（x=0，0.1，0.2，0.3，0.4）烧绿石铱酸盐。本文通过晶体结构、电输运和磁测量对空穴掺杂Bi 2 − xCaxIr 2 O 7 −δ进行了系统的研究。得到了具有立方结构的高结晶度Bi_（2-x）Ca_xIr_2 O_（7-δ）。由于Bi ~（3+）被离子半径相对较小的Ca ~（2+）随机取代，导致了无序和声子振荡，并使Ir-O带长度减小。发现掺杂样品表现出金属-绝缘体转变。对掺杂样品的磁性测量表明，掺杂后样品的磁性向SrIr 5+方向移动，反铁磁性减弱。
Bi2−xCaxIr2O7−δ(x=0, 0.1, 0.2, 0.3, and 0.4) pyrochlore iridates were prepared by the solid-state reaction method in air. In this paper we reported a systematic study of hole-doped Bi2−xCaxIr2O7−δby performing crystal structure, electrical transport and magnetic measurements. A high-crystallized Bi2–xCaxIr2O7–δwith a cubic structure was obtained. Because Bi3+was substituted in a random way by Ca2+which has relatively smaller ionic radius, disorder and phononic oscillations were induced and the the length of Ir–O bands were reduced. The doped samples were found to exhibit metal–insulator transition. Magnetic measurements on the doping samples indicated a shift towards nonmagnetic Ir5+, and the anti-ferromagnetism was weakened.