磁场对La_(2-x)Sr_xCuO_4单晶热导的影响研究

Influence of magnetic field on thermal conductivity of La_(2-x)Sr_xCuO_4 single crystals

报道了系列欠掺杂La2-xSrxCuO4(x=0·063,0·070,0·090,0·110,0·125)单晶的零场和加磁场情况下ab面和c方向的热导率与温度的关系曲线,测量温度范围从2到45K.研究发现ab面和c方向的热导率都受到磁场的压制.而且在磁场的作用下,热导压制率随温度变化的关系和场致反铁磁有序的增强与温度的依赖关系有高度相似性.认为磁场引起的ab面的热导压制主要是电子热导的变化所致,而c方向的压制则可能主要来源于声子热导的变化,它们均可能与磁场诱导下欠掺杂La2-xSrxCuO4中的某种电荷有序和磁有序的增强密切相关.

We have measured the temperature dependence of thermal conductivity in the ab-plane as well as c-axis of a series of underdoped La2-xSrxCuO4 (x = 0.063, 0.070, 0.090, 0.110, 0.125) single crystals under zero and 14 T magnetic field. It is found that the thermal conductivity in both ab plane and c-axis are suppressed by the application of the magnetic field parallel to the c-axis. The temperature dependence of the thermal conductivity suppression is quite similar to the previously reported behavior of the antiferromagnetic order induced by an applied magnetic field. We think that the field-induced thermal conductivity suppression in ab plane is due to the electronic contribution, while along c-axis it is due to the phonon contribution. Both the suppressions of the thermal conductivity in ab plane and along c-axis probably originate from the field-enhanced charge and spin ordering.