Multiple magnetic phase transitions, electrical and optical properties of FeTe2 single crystals

Single-crystalline FeTe2 in marcasite phase with orthorhombic structure was prepared via chemical vapor transport. Cooling FeTe2 single crystals from room temperature down to , multiple magnetic phase transitions were observed. Paramagnetic (PM) to antiferromagnetic (AFM) and then to ferromagnetic (...

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Bibliographic Details
Published in:Journal of physics. Condensed matter 2020-01, Vol.32 (3), p.035808-035808
Main Authors: Rahman, Azizur, Zhang, Dechen, Rehman, Majeed Ur, Zhang, Min, Wang, Xiangqi, Dai, Rucheng, Wang, Zhongping, Tao, Xiaoping, Zhang, Zengming
Format: Article
Language:English
Subjects:
FeTe
multiple magnetic transitions
optical properties
resistivity anomaly
single crystals
uniaxial magnetic anisotropy
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Summary:Single-crystalline FeTe2 in marcasite phase with orthorhombic structure was prepared via chemical vapor transport. Cooling FeTe2 single crystals from room temperature down to , multiple magnetic phase transitions were observed. Paramagnetic (PM) to antiferromagnetic (AFM) and then to ferromagnetic (FM) occurred at and for in-plane, and for out-of-plane, respectively. A strong uniaxial magnetic anisotropy was found due to FeTe6 octahedron distortion and structural modulation in FM region. The novel negative volume expansion (NVE) initiated in the vicinity of AFM to FM transition. An abrupt frequency shift of the most intense mode at and evolution of the Te-Te stretching mode near , corresponding to the phase transition from AFM to FM were observed. The temperature-dependent resistance revealed an anomaly (semiconductor to metallic transition) around AFM-FM transition, which can easily be suppressed and move to high temperature by the applied magnetic field. The results from XRD, Raman and resistivity indicated that the structural parameters, vibration frequency and transport are sensitive to the phase transition from AFM to FM. The nature of direct band gap with was identified through UV-Vis-NIR spectrum of FeTe2 single crystals at room temperature.
ISSN:0953-8984
1361-648X
DOI:10.1088/1361-648X/ab4b72