New Type of the Domain-Redistribution at Low Magnetic Fields in Phase II of CeB6
New Type of the Domain-Redistribution at Low Magnetic Fields in Phase II of CeB6
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新型低磁场重分布CeB6第二相
DOI：
10.1143/jpsj.81.104706
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
K. Kunimori
中科院分区：
文献类型：
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作者：
Y. Nakashima;A. Ino;S. Nagato;H. Anzai;H. Iwasawa;Y. Utsumi;H. Sato;M. Arita;H. Namatame;M. Taniguchi;T. Oguchi;Y. Aiura;I. Hase;K. Kihou;C. H. Lee;A. Iyo;and H. Eisaki;K. Kunimori
我们详细研究了CeB6在低磁场下在氧型反铁四极（AFQ）有序相II中的磁化强度（M），以阐明磁场对磁畴再分布的机制.虽然M_（IIA-IIB）相在101kOe以上是各向同性的，但在较低磁场下它是各向异性的，畴重分布（HcIIA-IIB）的磁场是高度各向异性的，M [001]<M [110]<M [111]和HcIIA-IIB [001]> HcIIA-IIB [110]> HcIIA-IIB [111]。这里，M [001]和HcIIA-IIB [001]分别是MandHcIIA-IIB for H [001]等。虽然在H = 0时存在Oxy-、Oyz-和Ozx-AFQ三个畴，但这些畴在磁场中相互耦合，通过磁场诱导的高阶Txz-反铁八极（AFO）相互作用，由HcIIA-IIB以上的Oxy、Oyz和Ozx四极矩的线性组合形成单畴态.畴重分布的发生是由于在H = 0时由Oxy-type AFQ有序稳定的小的四方晶格畸变与塞曼相互作用之间的竞争。对于H [001]，M最小，HcIIA-IIB最高，因为只有Oxy-domain与Txyz-AFO磁矩耦合产生有效铁磁相互作用，而Oyz和Ozx两个domain不耦合。对于H ε [111]，M在低于101kOe时最大，而HcIIA-IIB最小，因为在所有三个畴中都诱导了Txyz-AFO矩，并且随着磁场的增加，Oxy、Oyz和Ozx畴都连续地变为单畴。三个畴的线性组合系数通过磁场诱导的Txyz-AFO矩随磁场的变化而逐渐变化。这种连续的畴重分布不同于通常反铁磁体中畴间不存在耦合的畴重分布。
We performed the detailed investigation of the magnetization (M) of CeB6at low magnetic fields in theOxy-type antiferro-quadrupole (AFQ) ordered phase II to clarify the mechanism of the domain redistribution by magnetic field. AlthoughMin phase II is isotropic above ∼1 kOe, it is anisotropic at lower magnetic fields and the magnetic field of the domain redistribution (HcIIA–IIB) is highly anisotropic.M[001]<M[110]<M[111]andHcIIA–IIB[001]>HcIIA–IIB[110]>HcIIA–IIB[111]. Here,M[001]andHcIIA–IIB[001]areMandHcIIA–IIBforH∥[001], etc. respectively. Although there exist three domains ofOxy-,Oyz-, andOzx-AFQ ordered states atH=0 as in a usual AF magnet, these domains are coupled in magnetic fields and the single domain state is formed by the linear combination ofOxy,Oyz, andOzxquadrupole moments aboveHcIIA–IIBthrough the magnetic field induced higher orderTxyz-antiferro-octupole (AFO) interaction. The domain redistribution takes place due to the competition between the small tetragonal lattice distortion stabilized by theOxy-type AFQ order atH=0 and the Zeeman interaction. ForH∥[001],Mis smallest andHcIIA–IIBis highest because only theOxy-domain couples with theTxyz-AFO moment inducing the effective ferromagnetic interaction but the two domains ofOyzandOzxare not. ForH∥[111],Mis largest below ∼1 kOe andHcIIA–IIBis lowest because theTxyz-AFO moment is induced in all the three domains and each ofOxy,Oyz, andOzxdomain changes continuously to thesingle domain with increasing magnetic field. The coefficients of the linear combination of three domains gradually changes with magnetic field through the magnetic field inducedTxyz-AFO moment. This type of the continuous domain redistribution is different from that in the usual antiferro-magnet, where there does not exist the coupling among the different domains.