CAJ | 학술논문

系统研究了Gd_5Ge_4合金的晶体结构和低温磁化行为.结果表明,Gd_5Ge_4具有相分离特征,低温下出现反铁磁(AFM)和铁磁(FM)共存现象.由于相分离的存在导致127K时发生奈尔反铁磁转变.在外磁场诱导下,在4.2K以下发生AFM-FM磁转变,并导致台阶式磁化现象发生,但仅发生在第一次外加磁场增加过程中,表现出磁不可逆性.随磁场升高,在10K以下体系存在类台阶式响应和不可逆的磁滞行为,并在5572kA/m下均达到饱和磁化.在温度50～60K温区,磁循环所出现的台阶式磁化转变则是完全可逆的,更高温区域则表现为部分铁磁直至室温下的顺磁特性.
계통연구료Gd_5Ge_4합금적정체결구화저온자화행위.결과표명,Gd_5Ge_4구유상분리특정,저온하출현반철자(AFM)화철자(FM)공존현상.유우상분리적존재도치127K시발생내이반철자전변.재외자장유도하,재4.2K이하발생AFM-FM자전변,병도치태계식자화현상발생,단부발생재제일차외가자장증가과정중,표현출자불가역성.수자장승고,재10K이하체계존재류태계식향응화불가역적자체행위,병재5572kA/m하균체도포화자화.재온도50～60K온구,자순배소출현적태계식자화전변칙시완전가역적,경고온구역칙표현위부분철자직지실온하적순자특성.
Crystal structure and magnetization behavior at low temperature were studied systematically for Gd_5Ge_4 alloy. The results show that Gd_5Ge_4 is a phase-separated alloy and has antiferromagnetic (AFM) state and ferromagnetic (FM) state coexisting at low temperature. Abnormal Neel transition occurs at 127K due to phase separation. Below 4. 2K,AFM-FM transition induced by magnetic field can occur in Gd_5Ge_4, the transition is the main reason for magnetization step transition, and the magnetic transition only occurs when the magnetic field firstly increases, so it is irreversible. With magnetic field increasing,below 10K, there exist magnetization step behavior and hysteresis behavior, and the magnetization value reach saturation at 5572kA/m. At temperature 50-60K, the second magnetization almost goes along the first magnetization path, so the magnetization is entirely reversible. The Gd_5Ge_4 alloy is partly ferromagnetism below 120K and is completely para-magnetism at room temperature.