Super-Necking Crystal Growth and Structural and Magnetic Properties of SrTb2O4 Single Crystals

Si Wu; Yinghao Zhu; Haoshi Gao; Yinguo Xiao; Junchao Xia; Pengfei Zhou; Defang Ouyang; Zhen Li; Zhenqiang Chen; Zikang Tang; Hai-Feng Li

doi:10.1021/acsomega.0c01360

Super-Necking Crystal Growth and Structural and Magnetic Properties of SrTb₂O₄ Single Crystals

ACS Omega. 2020 Jun 29;5(27):16584-16594. doi: 10.1021/acsomega.0c01360. eCollection 2020 Jul 14.

Authors

Si Wu¹, Yinghao Zhu¹, Haoshi Gao^{1

2}, Yinguo Xiao³, Junchao Xia¹, Pengfei Zhou¹, Defang Ouyang², Zhen Li^{4

5}, Zhenqiang Chen^{4

5}, Zikang Tang¹, Hai-Feng Li¹

Affiliations

¹ Joint Key Laboratory of the Ministry of Education, Institute of Applied Physics and Materials Engineering, University of Macau, Avenida da Universidade, Taipa, Macao SAR 999078, China.
² State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences (ICMS), University of Macau, Avenida da Universidade, Taipa, Macao SAR 999078, China.
³ School of Advanced Materials, Peking University, Shenzhen Graduate School, Shenzhen 518055, China.
⁴ Guangdong Provincial Engineering Research Center of Crystal and Laser Technology, Guangzhou, Guangdong 510632, China.
⁵ Department of Optoelectronic Engineering, Jinan University, Guangzhou, Guangdong 510632, China.

Abstract

We report on single-crystal growths of the SrTb₂O₄ compound by a super-necking technique with a laser-floating-zone furnace and study the stoichiometry, growth mode, and structural and magnetic properties by scanning electronic microscopy, neutron Laue, X-ray powder diffraction, and the physical property measurement system. We optimized the growth parameters, mainly the growth speed, atmosphere, and the addition of a Tb₄O₇ raw material. Neutron Laue diffraction displays the characteristic feature of a single crystal. Our study reveals an atomic ratio of Sr:Tb = 0.97(2):2.00(1) and a possible layer by layer crystal growth mode. Our X-ray powder diffraction study determines the crystal structure, lattice constants, and atomic positions. The paramagnetic (PM) Curie-Weiss (CW) temperature θ_CW = 5.00(4) K, and the effective PM moment M _mea ^eff = 10.97(1) μ_B per Tb³⁺ ion. The data of magnetization versus temperature can be divided into three regimes, showing a coexistence of antiferromagnetic and ferromagnetic interactions. This probably leads to the magnetic frustration in the SrTb₂O₄ compound. The magnetization at 2 K and 14 T originates from both the Tb1 and Tb2 sites and is strongly frustrated with an expected saturation field at ∼41.5 T, displaying an intricate phase diagram with three ranges.