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arXiv 1303.2695cond-mat.supr-concond-mat.mtrl-scicond-mat.str-el
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新的ThCr2Si2-type BaMn2Bi2和K掺杂的组合物的晶体、磁性和电子性质

Crystals, magnetic and electronic properties of a new ThCr2Si2-type BaMn2Bi2 and K-doped compositions

Bayrammurad Saparov, Athena S. Sefat

摘要:

本文报道了从铋熔剂中结晶出的新的122三元过渡金属磷属元素化物BaMn_2Bi_2。BaMn_2Bi_2为ThCr_2Si_2型结构(I_4/mmm),a = 4.4902(3)μ m,c = 14.687(1)μ m,具有各向异性磁化率的反铁磁性和半导体性质,带隙Eg = 6 meV。热容结果证实了BaMn 2Bi 2的绝缘基态,电子剩余索末菲系数γ ~ 0.高温磁化结果表明,磁有序温度为TN ~ 400 K.通过Ba_(1-x)K_xMn_2Bi_2中的钾在BaMn_2Bi_2中进行空穴掺杂导致x = 0.10(1)、0.32(1)和0.36(1)的金属行为。随着K掺杂,观察到更多的磁各向异性行为。虽然在> 30%掺杂的晶体中,电阻率和低于4K的低场磁化数据下降,但没有零电阻或抗磁性的迹象。本文报道了BaMn_2Bi_2和Ba_(1-x)K_xMn_2Bi_2(0从粉末X射线衍射,各向异性的温度和磁场相关的磁化强度,温度和磁场相关的电阻率和热容的结果。

英文摘要:

This is a report on the new 122 ternary transition-metal pnictide of BaMn2Bi2, which is crystallized from bismuth flux. BaMn2Bi2 adopts ThCr2Si2-type structure (I4/mmm) with a = 4.4902(3) Å and c = 14.687(1) Å; it is antiferromagnetic with anisotropic magnetic susceptibility and semiconducting with a band gap of Eg = 6 meV. Heat capacity result confirms the insulating ground state in BaMn2Bi2 with the electronic residual Sommerfeld coefficient of γ ~ 0. The high temperature magnetization results show that magnetic ordering temperature is TN ~ 400 K. Hole-doping in BaMn2Bi2 via potassium in Ba1-xKxMn2Bi2 results in metallic behavior for x = 0.10(1), 0.32(1) and 0.36(1). With K-doping, more magnetically anisotropic behavior is observed. Although there is a downturn in electrical resistivity and low-field magnetization data below 4 K in > 30%-doped crystals, there is no sign of zero resistance or diamagnetism. This manuscript is a report on new materials of BaMn2Bi2 and Ba1-xKxMn2Bi2 (0 < x < 0.4). Results from powder X-ray diffraction, anisotropic temperature- and field-dependent magnetization, temperature-and field-dependent electrical resistivity, and heat capacity are presented.

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