Reinvestigation of Simultaneous Magnetic and Ferroelectric Phase Transitions in YMn2O5
Reinvestigation of Simultaneous Magnetic and Ferroelectric Phase Transitions in YMn2O5
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DOI：
10.1143/jpsj.73.1593
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发表时间：
2004-06
影响因子：
1.7
通讯作者：
Satoru Kobayashi;T. Osawa;H. Kimura;Y. Noda;I. Kagomiya;K. Kohn
中科院分区：
文献类型：
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作者：
Satoru Kobayashi;T. Osawa;H. Kimura;Y. Noda;I. Kagomiya;K. Kohn
利用单晶中子衍射和介电测量重新研究了弱铁电ymn2o5在铁电转变温度tc1周围的磁有序现象。除了先前报道的传播矢量q = (q x,0, q z)的二维调制不相称磁（2D-ICM）相和q =(1/2,0,1/4)的锁定相称磁（CM）相外，我们还观察到q = (q x,0,1/4)、q x ~ 0.492的一维- icm相，它出现在~ 1 K的狭窄温度区间，将2D-ICM和CM相分离。对应于T = 40.8 K和40.0 K时2d - icm到1d - icm和1d - icm到cm的相变，沿b轴的介电常数出现了一个尖峰和一个肩。这些结果表明，在ymn2o5中，铁电性与从2D-ICM到1D-ICM的磁相转变同时出现。
Magnetic ordering around the ferroelectric transition temperature T C1 of weakly ferroelectric YMn 2 O 5 has been reinvestigated by single-crystal neutron diffraction and dielectric measurements. Besides a two-dimensionally modulated incommensurate magnetic (2D-ICM) phase with the propagation vector q = ( q x ,0, q z ) and a lock-in commensurate magnetic (CM) one with q = (1/2,0,1/4) reported previously, we observed a 1D-ICM phase characterized by q = ( q x ,0,1/4) with q x ∼0.492 that appears in a narrow temperature interval of ∼1 K and separates the 2D-ICM and CM phases. Corresponding to the 2D-ICM-to-1D-ICM and 1D-ICM-to-CM phase transitions at T = 40.8 K and 40.0 K, a sharp peak and a shoulder in the dielectric constant along the b -axis were detected. These results suggest that the ferroelectricity appears simultaneously with the magnetic phase transition from the 2D-ICM to 1D-ICM phase in YMn 2 O 5 .