arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1105.1392cond-mat.mtrl-sci
收藏

La{0.70}Ca{0.30}Mn{1-x}Cr{x}O{3}的元素特异性和体磁性、电子和晶体结构研究

Investigation of element-specific and bulk magnetism, electronic and crystal structures of La{0.70}Ca{0.30}Mn{1-x}Cr{x}O{3}

H. Terashita, J. C. Cezar, F. M. Ardito, L. F. Bufaical, E. Granado

摘要:

用X射线吸收光谱(XAS)、X射线磁性圆二色性(XMCD)、高分辨X射线粉末衍射和体磁化强度测量研究了La{0.70}Ca{0.30}Mn{1-x}Cr{x}O{3}(x = 0.15,0.50和0.70)中的磁相互作用。在Mn和Cr L{2,3}边缘的XAS支持稳定的单价Cr{3+}离子和随x变化的Mn价态,而O K边缘XAS光谱揭示了由于与Mn和Cr 3d态混合而导致的接近费米能级的O 2 p态密度的局部最大值。当温度低于TN = 258 K时,当x=0.70时,发现了一个强的反铁磁态.对于x=0.15,结合XMCD和体磁化强度测量表明一个完全极化亚铁磁状态的Mn和Cr自旋低于Tc=224 K。当x=0.50时,在低于Tc=154 K时,Mn自旋占主导的亚铁磁分量减少.没有证据表明晶格异常,由于合作的电荷和轨道有序的X射线衍射发现所有样品。该系统的磁性是合理的铁磁Mn-Mn双交换和反铁磁Cr-Cr和Cr-Mn超交换相互作用的竞争。

英文摘要:

The magnetic interactions in La{0.70}Ca{0.30}Mn{1-x}Cr{x}O{3} (x = 0.15, 0.50 and 0.70) are investigated by x-ray absorption spectroscopy (XAS), x-ray magnetic circular dichroism (XMCD), high-resolution x-ray powder diffraction, and bulk magnetization measurements. XAS in the Mn and Cr L{2,3} edges support stable single valent Cr{3+} ions and a varying Mn valence state with x, while the O K edge XAS spectrum reveals local maxima in the O 2p density of states close to the Fermi level due to mixing with Mn and Cr 3d states. A robust antiferromagnetic state is found for x=0.70 below TN = 258 K. For x=0.15, combined XMCD and bulk magnetization measurements indicate a fully polarized ferrimagnetic state for the Mn and Cr spins below Tc=224 K. For x=0.50, a reduced ferrimagnetic component dominated by Mn spins is present below Tc=154 K. No evidence of lattice anomalies due to cooperative charge and orbital orderings is found by x-ray diffraction for all samples. The magnetic properties of this system are rationalized in terms of a competition of ferromagnetic Mn-Mn double exchange and antiferromagnetic Cr-Cr and Cr-Mn superexchange interactions.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑