Hansen Anna-Lena, Kremer Reinhard K, Heppke Eva M, Lerch Martin, Bensch Wolfgang
Christian-Albrechts-Universität zu Kiel, Institut für Anorganische Chemie, Max-Eyth-Str. 2, 24118 Kiel, Germany.
Institute for Applied Materials-Energy Storage Systems-IAM-ESS, Karlsruhe Institute of Technology-KIT, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
ACS Omega. 2021 May 10;6(20):13375-13383. doi: 10.1021/acsomega.1c01412. eCollection 2021 May 25.
Nanosized samples of the cubic thiospinel FeCrS were synthesized by ball milling of FeS and CrS precursors followed by a distinct temperature treatment between 500 and 800 °C. Depending on the applied temperature, volume weighted mean ( ) particle sizes of 56 nm (500 °C), 86 nm (600 °C), and 123 nm (800 °C) were obtained. All samples show a transition into the ferrimagnetic state at a Curie temperature of ∼ 167 K only slightly depending on the annealing temperature. Above , ferromagnetic spin clusters survive and Curie-Weiss behavior is observed only at ≫ , with depending on the heat treatments and the external magnetic field applied. Zero-field-cooled and field-cooled magnetic susceptibilities diverge significantly below in contrast to what is observed for conventionally solid-state-prepared polycrystalline samples. In the low-temperature region, all samples show a transition into the orbital ordered state at about 9 K, which is more pronounced for the samples heated to higher temperatures. This observation is a clear indication that the cation disorder is very low because a pronounced disorder would suppress this magnetic transition. The unusual magnetic properties of the samples at low temperatures and different external magnetic fields can be clearly related to different factors like structural microstrain and magnetocrystalline anisotropy.
通过对FeS和CrS前驱体进行球磨，然后在500至800°C之间进行特定温度处理，合成了立方硫代尖晶石FeCrS的纳米级样品。根据所施加的温度，获得了体积加权平均（ ）粒径分别为56 nm（500°C）、86 nm（600°C）和123 nm（800°C）的样品。所有样品仅略微依赖于退火温度，在居里温度 约为167 K时转变为亚铁磁状态。高于 时，铁磁自旋簇仍然存在，并且仅在 ≫ 时观察到居里 - 外斯行为，其中 取决于热处理和所施加的外部磁场。与传统固态制备的多晶样品所观察到的情况相反，零场冷却和场冷却磁化率在 以下显著发散。在低温区域，所有样品在约9 K时转变为轨道有序状态，对于加热到更高温度的样品，这种转变更为明显。这一观察结果清楚地表明阳离子无序非常低，因为明显的无序会抑制这种磁转变。样品在低温和不同外部磁场下的异常磁性可以明显地与结构微应变和磁晶各向异性等不同因素相关联。
