Das A, Neogi S K, Banerjee A, Tayal A, Bandyopadhyay S
Department of Physics, University of Calcutta, 92 A.P.C. Road, Kolkata 700009, India.
Department of Physics, Adamas University, Barasat, West Bengal, India.
J Phys Condens Matter. 2023 Sep 15;35(50). doi: 10.1088/1361-648X/acf6a1.
Low-dimensional quantum spin ½ system CuVOhas been investigated in the framework of Mn-substitution at the Cu site, which is really un-investigated. The studied compounds CuMnVO(= 0, 0.05, 0.1 and 0.15) have been synthesized and characterized structurally, spectroscopically, local structurally and magnetically via x-ray diffraction, Raman, x-ray absorption and temperature, field dependent magnetization measurements respectively. Although CuVOcan be found inand-phase, however all of the studied compounds are found in single orthorhombic-phase which has crucial magneto-electric application potential. Temperature dependent Raman spectra indicated anharmonic phonon-phonon scattering but there is no spin-phonon coupling for VOvibrational modes. The local structure probed via x-ray absorption near edge structure and extended x-ray absorption fine structure spectroscopy at 15 K, 300 K indicates Cu, Vand mixed valent Mnand Mnionic states and justified local structure for the probed ions. Magnetic measurements indicate long-range antiferromagnetic ordering with doping independent Neel temperature (32.5 K). Further observations are strong magnetic hysteresis at 5 K (due to canted spin structure), zero field exchange-bias and their noteworthy enhancement upon Mn-substitution. Interesting correlation between structural parameters and magnetic exchanges has been developed.
低维量子自旋1/2体系CuVO在Cu位点进行Mn替代的框架下得到了研究，这一领域此前确实未被研究过。所研究的化合物CuMnVO（x = 0、0.05、0.1和0.15）已通过X射线衍射、拉曼光谱、X射线吸收以及温度和磁场依赖的磁化测量分别进行了结构、光谱、局部结构和磁性表征。尽管CuVO可以在α相和β相中找到，但所有研究的化合物都处于具有关键磁电应用潜力的单一正交相中。温度依赖的拉曼光谱表明存在非谐声子-声子散射，但VO振动模式不存在自旋-声子耦合。通过15 K、300 K下的X射线吸收近边结构和扩展X射线吸收精细结构光谱探测的局部结构表明存在Cu、V以及混合价态的Mn²⁺和Mn³⁺离子态，并证明了所探测离子的局部结构合理。磁性测量表明存在长程反铁磁有序，奈尔温度（32.5 K）与掺杂无关。进一步的观察结果是在5 K时出现强磁滞（由于倾斜的自旋结构）、零场交换偏置以及Mn替代后它们显著增强了。已经建立了结构参数与磁交换之间的有趣关联。
