摘要
Sr_(2)CrOsO_(6)具有双钙钛矿氧化物中最高的磁转变温度(725 K)。使用体积更小的Ca离子取代Sr离子后得到了Ca_(2)CrOsO_(6),其磁转变温度同样高于室温。进一步使用d轨道更加离域化的Mo离子取代Cr离子,得到了Ca_(2)MoOsO_(6)。通过密度泛函理论,系统地计算了双钙钛矿氧化物Sr_(2)CrOsO_(6)、Ca_(2)CrOsO_(6)和Ca_(2)MoOsO_(6)的电子结构和磁光克尔效应,电子结构表明,三种材料均为半导体。Sr_(2)CrOsO_(6)和Ca_(2)CrOsO_(6)的电子结构非常相似,Ca_(2)MoOsO_(6)的带隙极小,仅有0.10 eV。观察磁光克尔效应谱线,三种材料在红外到可见光谱的范围内均表现出显著的磁光克尔效应。Sr_(2)CrOsO_(6)、Ca_(2)CrOsO_(6)和Ca_(2)MoOsO_(6)的最大克尔旋角分别为1.18°、0.98°和0.65°。三种材料的最大克尔旋角均大于0.2°,是理想的磁光材料。计算结果表明化合物内同时包含3d(4d)和5d过渡金属离子有助于形成显著的磁光克尔效应。对光学电导率张量的分析表明,三种材料的磁光克尔谱线峰值源自带间跃迁,并且由光学电导率张量的非对角元虚部主导。
Sr_(2)CrOsO_(6)has the highest magnetic transition temperature(725 K)among the double perovskite oxides.Ca_(2)CrOsO_(6)was obtained by replacing Sr ions with smaller volume Ca ions,and the magnetic transition temperature was higher than room temperature.Further substitution of Cr ions by Mo ions with more delocalized d orbitals yielded Ca_(2)MoOsO_(6).The electronic structures and magneto-optical Kerr effects of the double perovskite oxides Sr_(2)CrOsO_(6),Ca_(2)CrOsO_(6)and Ca_(2)MoOsO_(6)have been systematically calculated by density functional theory.The electronic structures indicate that all three materials are semiconductors.The electronic structures of Sr_(2)CrOsO_(6)and Ca_(2)CrOsO_(6)are very similar,and the band gap of Ca_(2)MoOsO_(6)is extremely small,only 0.10 eV.Observing the magneto-optical Kerr effect line,all three materials show significant magneto-optical Kerr effects in the range of infrared to visible spectrum.The maximum Kerr rotation angles of Sr_(2)CrOsO_(6),Ca_(2)CrOsO_(6)and Ca_(2)MoOsO_(6)are 1.18°,0.98°and 0.65°.The maximum Kerr rotation angle of the three materials is greater than 0.2°,which makes them to be ideal magneto-optical materials.The calculated results show that the inclusion of both 3d(4d)and 5d transition metal ions in the compound contributes to the significant magneto-optical Kerr effect.Analysis of the optical conductivity tensor shows that the peak of the magneto-optical Kerr line of three materials originates from the interband transition and is dominated by the imaginary part of the off-diagonal element of optical conductivity tensor.
作者
刘派
祖宁宁
李瑞
LIU Pai;ZU Ningning;LI Rui(College of Science,Qiqihar University,Qiqihar 161003,China)
出处
《人工晶体学报》
CAS
北大核心
2024年第2期267-275,共9页
Journal of Synthetic Crystals
基金
黑龙江省省属高等学校基本科研业务费青年创新人才项目(135309343)
国家自然科学基金(21703112)。
关键词
双钙钛矿氧化物
磁光克尔效应
带间跃迁
第一性原理
自旋轨道耦合
double perovskite oxide
magneto-optical Kerr effect
interband transition
first principle
spin orbit coupling
