Interplay between spin-density wave and 3d local moments with random exchange in a molecular conductor
Interplay between spin-density wave and 3d local moments with random exchange in a molecular conductor
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自旋密度波与分子导体中随机交换的 3d 局部矩之间的相互作用
DOI：
10.1103/physrevb.93.075124
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
H. Kitagawa
中科院分区：
文献类型：
--
作者：
G. Kawaguchi;M. Maesato;T. Komatsu;T. Imakubo;H. Kitagawa
本文报道了阴离子混合分子导体（DIETSe）[DIETSe = diiodo（ethylenedithio）tetraselenafulvalene;，Ga]的高压输运测量结果。它们在环境压力下经历低于9 K的金属-绝缘体（M-I）转变，这通过施加压力而被抑制，表明由准一维（Q1 D）费米表面的嵌套不稳定性引起的自旋密度波（SDW）转变，如在母体化合物（DIETSe）（，Ga）中所观察到的。在金属态，Q1 D费米面的存在被证实通过观察Lebed共振。（，Ga）盐的SDW_（1，2）的临界压力明显低于（= Fe，Ga）盐的SDW_（1，2）的临界压力，表明存在化学压力效应。以上，场诱导的SDW转变出现，证明了在两种盐的磁阻（MR）的扭结结构。盐也显示了反铁磁（AF）有序的自旋在4 K，低于此显着的自旋-电荷耦合观察。在高压下，自旋翻转场上方出现高达150%的正MR变化。在低压下，特别是低于低压时，在自旋翻转场处的MR中出现下沉或扭结结构，这在低温下显示出异常大的滞后（K）。磁滞区明显减小，随着压力的增加，强烈表明，共存的SDW起着重要的作用，除了随机交换相互作用的磁滞增强。
We present the results of high-pressure transport measurements on the anion-mixed molecular conductors (DIETSe)[DIETSe = diiodo(ethylenedithio)tetraselenafulvalene;, Ga]. They undergo a metal-insulator (M-I) transition below 9 K at ambient pressure, which is suppressed by applying pressure, indicating a spin-density-wave (SDW) transition caused by a nesting instability of the quasi-one-dimensional (Q1D) Fermi surface, as observed in the parent compounds (DIETSe)(, Ga). In the metallic state, the existence of the Q1D Fermi surface is confirmed by observing the Lebed resonance. The critical pressures of the SDW,, of the(, Ga) salts are significantly lower than those of the the(= Fe, Ga) salts, suggesting chemical pressure effects. Above, field-induced SDW transitions appear, as evidenced by kink structures in the magnetoresistance (MR) in both salts. Thesalt also shows antiferromagnetic (AF) ordering ofspins at 4 K, below which significant spin-charge coupling is observed. A large positive MR change up to 150% appears above the spin-flop field at high pressure. At low pressure, in particular below, a dip or kink structure appears in MR at the spin-flop field, which shows unconventionally large hysteresis at low temperatureK). The hysteresis region clearly decreases with increasing pressure towards, strongly indicating that the coexisting SDW plays an important role in the enhancement of magnetic hysteresis besides the random exchange interaction.