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Evolution of magnetic phases inSmCrO3: A neutron diffraction and magnetometric study
Physical Review B ( IF 3.7 ) Pub Date : 2017-11-17 00:00:00 , DOI: 10.1103/physrevb.96.174421
Malvika Tripathi , R. J. Choudhary , D. M. Phase , T. Chatterji , H. E. Fischer

The classical belief about the mechanism of spin reorientation phase transition (SRPT) and ground-state magnetic structure in SmCrO3 has become intriguing because of inconsistent bulk magnetization observations. The presence of highly neutron-absorbing Sm atom has so far evaded the determination of microscopic magnetic structure. In the present report, we have utilized very high-energy “hot neutrons” to overcome the Sm absorption and to determine the thermal evolution of magnetic configurations. Unambiguously, three distinct phases are observed: the uncompensated canted antiferromagnetic structure Γ4(Gx,Ay,Fz;FzR) occurring below the Néel temperature (TN=191 K), the collinear antiferromagnetic structure Γ1(Ax,Gy,Cz;CzR) occurring below 10 K, and a nonequilibrium configuration with cooccurring Γ1 and Γ4 phases in the neighborhood of the SRPT (10 K T 40 K). In differing to the earlier predictions, we divulge the SRPT to be a discontinuous transition where chromium spins switch from the ab crystallographic plane to the bc crystallographic plane in a discrete manner with no allowed intermediate configuration. The canting angle of chromium ions in the ab plane is unusually not a thermal constant, rather it is empirically discerned to follow exponential behavior. The competition between magnetocrystalline anisotropy and free energy derived by isotropic and antisymmetric exchange interactions between different pairs of magnetic ions is observed to govern the mechanism of SRPT.

中文翻译:

SmCrO3中磁性相的演化:中子衍射和磁力分析研究

关于自旋取向相变(SRPT)和基态磁性结构机理的经典观点。 铬铬3由于不一致的大块磁化观测值而引起人们的兴趣。迄今为止,高中子吸收性Sm原子的存在避免了微观磁性结构的确定。在本报告中,我们利用了非常高能量的“热中子”来克服Sm吸收并确定磁性结构的热演化。明确地观察到三个不同的阶段:未补偿的倾斜反铁磁结构Γ4GX一个ÿFž;Fž[R 发生在Néel温度以下(Ťñ=191 K),共线反铁磁结构 Γ1个一个XGÿCž;Cž[R 发生在10 K以下,并且非平衡配置同时发生 Γ1个Γ4 SRPT附近的相位(10 K Ť40 K)。与先前的预测不同,我们将SRPT泄露为不连续的过渡,其中铬的自旋从一个-b 晶体平面 b-C晶面以离散方式存在,不允许有中间构型。铬离子在样品中的倾斜角一个-b平面通常不是热常数,而是根据经验可以遵循指数行为。磁晶各向异性和自由能之间的竞争是由不同对的磁离子之间的各向同性和反对称交换相互作用产生的,从而控制了SRPT的机理。
更新日期:2017-11-17
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