A new tetragonal phase in CoFeCrGe Heusler alloy
A new tetragonal phase in CoFeCrGe Heusler alloy
复制标题
CoFeCrGe Heusler 合金中的新四方相
DOI：
10.1016/j.matchar.2017.12.036
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发表时间：
2018
影响因子：
4.7
通讯作者：
Sellmyer, D.J.
中科院分区：
文献类型：
--
作者：
Jin, Y.-L.;Li, X.-Z.;Sellmyer, D.J.
采用熔体快淬法制备了CoFeCrGe薄带，并分别在300 °C和500 °C下退火4 h。快淬态CoFeCrGe薄带具有B2型结构，a = 0.287nm。在300 °C退火的CoFeCrGe薄带中，部分无序时主要由a = 0.578nm的L21型结构组成，进一步无序时主要由a = 0.289nm的B2型结构组成。在500 °C退火的薄带由三种化合物组成，其平均成分为Co26.0Fe26.5Cr23.5Ge24.0、Co3.8Fe6.4Cr68.5Ge21.3和Co53.4Fe30.4Cr8.6Ge7.6，按体积百分比从大到小的顺序列出。Co_（26.0）Fe_（26.5）Cr_（23.5）Ge_（24.0）在部分无序时为L_（21）型结构，a = 0.571 nm，进一步无序时为B_（2）型结构，a = 0.286 nm。第二化合物Co3.8Fe6.4Cr68.5Ge21.3具有立方Cr3Ge结构，a = 0.461nm。三元化合物Co_（53.4）Fe_（30.4）Cr_（8.6）Ge_（7.6）是一种新的四方晶系结构，其晶格参数为a = 0.76nm，c= 0.284nm。第三富（Co，Fe）相通常嵌入第二富Cr相的基体中，但两相之间没有特殊的取向关系。在300 °C和500 °C下退火的样品的磁滞回线的差异已被解释为新的四方晶相的出现。元素掺杂是进一步发展单一的四方相或增加其含量的可能途径。
CoFeCrGe ribbons were prepared by melt spinning and then annealed at 300 °C for 4 h and 500 °C for 4 h, respectively. The as-spun ribbons of CoFeCrGe have the B2 type structure witha= 0.287 nm. The CoFeCrGe ribbons annealed at 300 °C are composed mainly of the L21type structure witha= 0.578 nm in partial disorder and the B2 type structure witha= 0.289 nm in further disorder case. The ribbons annealed at 500 °C are composed of three compounds with average compositions of Co26.0Fe26.5Cr23.5Ge24.0, Co3.8Fe6.4Cr68.5Ge21.3and Co53.4Fe30.4Cr8.6Ge7.6, listed in a sequence of volume percentage from major to minor. The primary compound Co26.0Fe26.5Cr23.5Ge24.0is the L21-type structure witha= 0.571 nm in partial disorder and the B2 type structure witha= 0.286 nm in further disorder case. The secondary compound Co3.8Fe6.4Cr68.5Ge21.3has a cubic Cr3Ge structure witha= 0.461 nm. The tertiary compound Co53.4Fe30.4Cr8.6Ge7.6is a new tetragonal structure with lattice parametersa= 0.76 nm,c= 0.284 nm, which were determined by using tilt-series electron diffraction technique in this work. The tertiary (Co, Fe)-rich phase is usually embedded in the matrix of the secondary Cr-rich phase, but there is no special orientation between the two phases. The difference in the magnetic hysteresis loops of the samples annealed at 300 °C and 500 °C has been interpreted as the appearance of the new tetragonal crystalline phase. Element doping is the possible way for further developing the single tetragonal phase or increasing the amount of this phase.
影响因子：
4
作者：
Liu, Y.;George, T. A.;Sellmyer, D. J.
通讯作者：
Sellmyer, D. J.