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arXiv 1209.2783cond-mat.str-el
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手性helimagnet Cr1/3NbS2单晶的磁相变

Magnetic phase transitions in single crystals of the chiral helimagnet Cr1/3NbS2

N. J. Ghimire, M. A. McGuire, D. S. Parker, B. Sipos, S. Tang, J. -Q. Yan, B. C. Sales, D. Mandrus

摘要:

通过对手性螺旋磁体Cr_(1/3)NbS_2单晶的磁性、输运和热性质的测量以及第一性原理电子结构的计算,研究了手性螺旋磁体Cr_(1/3)NbS_2的磁性、输运和热性质。从测量的磁场和温度依赖性的磁化垂直于c轴施加的字段,磁相图已被构建在附近的相变。在120 K附近发生从顺磁相到磁有序相的转变。随着磁场的增加和温度低于120 K,该材料在900 Oe附近经历从螺旋磁相到孤立晶格相的转变,然后在1300 Oe附近转变为铁磁相。发现这些转变强烈影响电输运。在120 K附近冷却时电阻率急剧下降,并且在磁阻中从螺旋基态到相称铁磁态的自旋重取向是明显的。在高磁场下,在磁转变温度附近观察到大的磁电阻(140 kOe时为55%).热容和电子结构计算表明,在磁有序态中费米能级的态密度较低。自旋涨落的影响对于理解Cr 1/3 NbS 2在磁有序转变附近和之上的行为可能是重要的。

英文摘要:

The chiral helimagnet Cr1/3NbS2 has been investigated by magnetic, transport and thermal properties measurements on single crystals and by first principles electronic structure calculations. From the measured field and temperature dependence of the magnetization for fields applied perpendicular to the c axis, the magnetic phase diagram has been constructed in the vicinity of the phase transitions. A transition from a paramagnetic to a magnetically ordered phase occurs near 120 K. With increasing magnetic field and at temperatures below 120 K, this material undergoes transitions from a helimagnetic to a soliton-lattice phase near 900 Oe, and then to a ferromagnetic phase near 1300 Oe. The transitions are found to strongly affect the electrical transport. The resistivity decreases sharply upon cooling near 120 K, and the spin reorientation from the helimagnetic ground state to the commensurate ferromagnetic state is evident in the magnetoresistance. At high fields a large magnetoresistance (55 % at 140 kOe) is observed near the magnetic transition temperature. Heat capacity and electronic structure calculations show the density of states at the Fermi level is low in the magnetically ordered state. Effects of spin fluctuations are likely important in understanding the behavior of Cr1/3NbS2 near and above the magnetic ordering transitions.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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