{"title":"Thermal expansion, quasi-metamagnetism and spin-reorientation in Fe7Se8 substituted with chromium","authors":"","doi":"10.1016/j.physb.2024.416580","DOIUrl":null,"url":null,"abstract":"<div><div>The properties of the selenide compound Fe<sub>7</sub>Se<sub>8</sub> with a layered crystal structure of the NiAs type are strongly influenced by substitutions and the distribution of vacancies. The Cr-substituted compound Fe<sub>6.5</sub>Cr<sub>0.5</sub>Se<sub>8</sub> was obtained in single-crystalline form and studied by x-ray diffraction, energy-dispersive x-ray spectroscopy, thermal expansion and magnetization measurements. It was observed that the partial replacement of iron with chromium led to a twofold decrease in spontaneous volume magnetostriction due to changes in competing magnetoelastic contributions to thermal expansion along and perpendicular to the <em>c</em> axis of the crystal. The replacement of iron with chromium slightly decreases the Néel temperature (from 440 to 435 K) and significantly enhances the critical temperature of spin reorientation transition <em>T</em><sub>sr</sub> (from 115 to 160 K), apparently due to a change in the crystal electric field. Below 160 K, the Fe<sub>6.5</sub>Cr<sub>0.5</sub>Se crystal is found to exhibit metamagnetic-like behavior of the magnetization when the magnetic field is applied along the <em>c</em> axis. A jump-like change of the magnetization at a critical field up to ∼10 kOe is attributed to the presence of pinning centers of domain walls presumably due the ordering of chromium atoms substituting iron in cationic layers.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8000,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Physica B-condensed Matter","FirstCategoryId":"101","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0921452624009219","RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"PHYSICS, CONDENSED MATTER","Score":null,"Total":0}
引用次数: 0
Abstract
The properties of the selenide compound Fe7Se8 with a layered crystal structure of the NiAs type are strongly influenced by substitutions and the distribution of vacancies. The Cr-substituted compound Fe6.5Cr0.5Se8 was obtained in single-crystalline form and studied by x-ray diffraction, energy-dispersive x-ray spectroscopy, thermal expansion and magnetization measurements. It was observed that the partial replacement of iron with chromium led to a twofold decrease in spontaneous volume magnetostriction due to changes in competing magnetoelastic contributions to thermal expansion along and perpendicular to the c axis of the crystal. The replacement of iron with chromium slightly decreases the Néel temperature (from 440 to 435 K) and significantly enhances the critical temperature of spin reorientation transition Tsr (from 115 to 160 K), apparently due to a change in the crystal electric field. Below 160 K, the Fe6.5Cr0.5Se crystal is found to exhibit metamagnetic-like behavior of the magnetization when the magnetic field is applied along the c axis. A jump-like change of the magnetization at a critical field up to ∼10 kOe is attributed to the presence of pinning centers of domain walls presumably due the ordering of chromium atoms substituting iron in cationic layers.
具有 NiAs 型层状晶体结构的硒化物 Fe7Se8 的性质受到取代和空位分布的强烈影响。我们获得了单晶形式的铬取代化合物 Fe6.5Cr0.5Se8,并通过 X 射线衍射、能量色散 X 射线光谱、热膨胀和磁化测量对其进行了研究。研究发现,用铬部分替代铁会导致自发体积磁致伸缩降低两倍,这是由于沿晶体 c 轴和垂直于晶体 c 轴的热膨胀的磁弹性竞争贡献发生了变化。用铬替代铁后,奈尔温度略有降低(从 440 K 降至 435 K),而自旋重新定向转变临界温度 Tsr 则显著升高(从 115 K 升至 160 K),这显然是由于晶体电场发生了变化。在 160 K 以下,当磁场沿 c 轴施加时,Fe6.5Cr0.5Se 晶体的磁化表现出类似元磁性。在临界磁场高达 ∼10 kOe 时,磁化率会发生跳跃式变化,这可能是由于在阳离子层中以铬原子取代铁的有序化作用导致了畴壁钉住中心的存在。
期刊介绍:
Physica B: Condensed Matter comprises all condensed matter and material physics that involve theoretical, computational and experimental work.
Papers should contain further developments and a proper discussion on the physics of experimental or theoretical results in one of the following areas:
-Magnetism
-Materials physics
-Nanostructures and nanomaterials
-Optics and optical materials
-Quantum materials
-Semiconductors
-Strongly correlated systems
-Superconductivity
-Surfaces and interfaces