Lin Yi-Qiang, Jiang Hao, Li Hua-Xun, Song Shi-Jie, Wu Si-Qi, Ren Zhi, Cao Guang-Han
Department of Physics, Zhejiang University, Hangzhou 310027, China.
School of Physics and Optoelectronics, Xiangtan University, Xiangtan 411105, China.
Materials (Basel). 2022 Jan 21;15(3):802. doi: 10.3390/ma15030802.
We report synthesis, crystal structure, and physical properties of Sr2Cr2AsO3. The new compound crystallizes in a Sr2GaO3CuS-type structure with two distinct Cr sites, Cr(1) in the perovskite-like block layers of "Sr3Cr2O6" and Cr(2) in the ThCr2Si2-type layers of "SrCr2As2". An inter-block-layer charge transfer is explicitly evidenced, which dopes electrons in the CrO2 planes and simultaneously dopes holes into the CrAs layers. Measurements of electrical resistivity, magnetization, and specific heat, in combination with density-functional theoretical calculations, indicate that the title material is an antiferromagnetic metal. The Cr(2) magnetic moments in the CrAs layers order at 420 K, while the Cr(1) spins in the CrO2 planes show quasi-two-dimensional magnetism with long-range ordering below 80 K. Both Néel temperatures are significantly reduced, compared with those of the cousin material Sr2Cr3As2O2, probably due to the intrinsic charge-carrier doping. Complex re-entrant magnetic transitions with a huge magnetic hysteresis were observed at low temperatures.
我们报道了Sr₂Cr₂AsO₃的合成、晶体结构和物理性质。这种新化合物结晶为Sr₂GaO₃CuS型结构，有两个不同的Cr位点，Cr(1)位于“Sr₃Cr₂O₆”的类钙钛矿块状层中，Cr(2)位于“SrCr₂As₂”的ThCr₂Si₂型层中。明确证实了块层间的电荷转移，该转移在CrO₂平面中注入电子，同时在CrAs层中注入空穴。电阻率、磁化强度和比热的测量结果，结合密度泛函理论计算，表明该标题材料是一种反铁磁金属。CrAs层中的Cr(2)磁矩在420 K时有序排列，而CrO₂平面中的Cr(1)自旋在80 K以下表现出具有长程有序的准二维磁性。与同族材料Sr₂Cr₃As₂O₂相比，这两个奈尔温度都显著降低，这可能归因于本征电荷载流子掺杂。在低温下观察到了具有巨大磁滞的复杂再入磁转变。
