Effect of nitrogen substitution on the structural and magnetic ordering transitions of NiCr2O4

	Effect of nitrogen substitution on the structural and magnetic ordering transitions of NiCr2O4
	Liu, Xin 1,2; Yin, Nan 1; Thomas, Tiju 3; Yang, Minghui 1; Wang, Junhu 1,2; Shi, Quan 1
刊名	RSC Advances
	2016
卷号	6 期号:113 页码:112140-112147
英文摘要	The nitrogen (N) doped spinel NiCr2O4 has been synthesized at 773 K (N500) and 873 K (N600) by ammonolysis of NiCr2O4 powders to study the effect of anion doping on its structural and magnetic properties. The N contents are determined by thermogravimetric oxidation, yielding a composition that can be described as NiCr2O3.68N0.21 (N500) and NiCr2O3.55N0.30 (N600). X-ray photoelectron spectroscopic studies suggest that N3- species partly substitute the oxygen in the lattice and oxygen vacancies exist in the N doped samples. There is evidence that in the nitrided sample, the Cr ion is most likely in a mixed oxidation state. As the N content increases, the structure at room temperature changes from tetragonal to the cubic phase; N500 is only partially tetragonal; N600 is completely cubic. Such structural change is the consequence of the depression of the cooperative Jahn-Teller effect of Ni2+ in the tetrahedral A site caused by the presence of N3-. Combined heat capacity and temperature dependent magnetic susceptibility measurements give clear evidence of the magnetic and structural transitions in the N doped NiCr2O4. The Jahn-Teller transition temperatures decrease with increasing N content; this is likely due to increased covalency and hence enhanced contribution of the angular momentum and the spin-orbit coupling to local chemical bonding around Ni2+. Antiferromagnetic transitions are observed at T-S = 23 K and 22 K for N500 and N600, respectively. Hence there is indeed a lowering of transition when compared to pure NiCr2O4 (28 K). The magnetic loops at different temperatures confirm that the material behaves as a paramagnet over a wide range of temperatures T similar to 80-350 K. The material also exhibits a canted ferrimagnetic structural transition between 30 and 70 K. We also report evidence for increased frustration and lowered correlation length in N doped compounds compared to the parent NiCr2O4. The present study on N- doping effects on the structure and magnetic properties of this NiCr2O4 is expected to be useful for tailoring the ferric phase transitions through anion substitutions.
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Chemistry, Multidisciplinary
关键词[WOS]	TEMPERATURE HEAT-CAPACITY ; RAY PHOTOELECTRON-SPECTROSCOPY ; NICKEL CHROMITE ; THIN-FILMS ; ELECTRONIC-PROPERTIES ; NEUTRON-DIFFRACTION ; SPINEL OXIDES ; OXYNITRIDE ; METAL ; XPS
收录类别	SCI
语种	英语
WOS记录号	WOS:000389708700056
内容类型	期刊论文
源URL	[http://cas-ir.dicp.ac.cn/handle/321008/150423]
专题	大连化学物理研究所_中国科学院大连化学物理研究所
作者单位	1.Chinese Acad Sci, Dalian Inst Chem Phys, Dalian 116023, Peoples R China 2.Chinese Acad Sci, Dalian Inst Chem Phys, Mossbauer Effect Data Ctr, Dalian 116023, Peoples R China 3.Indian Inst Technol Madras, Dept Met & Mat Engn, Madras 600036, Tamil Nadu, India
推荐引用方式 GB/T 7714	Liu, Xin,Yin, Nan,Thomas, Tiju,et al. Effect of nitrogen substitution on the structural and magnetic ordering transitions of NiCr2O4[J]. RSC Advances,2016,6(113):112140-112147.
APA	Liu, Xin,Yin, Nan,Thomas, Tiju,Yang, Minghui,Wang, Junhu,&Shi, Quan.(2016).Effect of nitrogen substitution on the structural and magnetic ordering transitions of NiCr2O4.RSC Advances,6(113),112140-112147.
MLA	Liu, Xin,et al."Effect of nitrogen substitution on the structural and magnetic ordering transitions of NiCr2O4".RSC Advances 6.113(2016):112140-112147.