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

Abstract

We report on single-crystal growths of the SrTb 2 O 4 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 Tb 4 O 7 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 Tb 3+ 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 SrTb 2 O 4 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.

Insights into the structural symmetry of single-crystal YCrO$_3$ from synchrotron X-ray diffraction

“…We prepared polycrystalline YCrO 3 samples by solid state reaction [41] with a procedure similar to the previously-reported one [9,10] UM) well-equipped at the University of Macau, Macao, China [42,43].…”

Enhanced magnetocaloric effect and magnetic phase diagrams of single-crystalGdCrO3

“…Chemically stoichiometric raw materials of Gd 2 O 3 (ALFA AESAR, 99.9%) and Cr 2 O 3 (ALFA AESAR, 99.6%) were milled and mixed by a Vibratory Micro Mill (FRITSCH PULVERISETTE 0) with an addition of 5-10% Cr 2 O 3 compound. The mixture was calcined twice at ambient air pressure: Once was at 1100 • C for 24 h, and the other at 1200 • C for 36 h. We grew GdCrO 3 single crystals with a laser diode FZ furnace (Model: LD-FZ-5-200W-VPO-PC-UM) [19][20][21].…”

Colossal Negative Magnetoresistance Effect in a La1.37Sr1.63Mn2O7 Single Crystal Grown by Laser-Diode-Heated Floating-Zone Technique

“…Compared with the traditional floating-zone furnace with IR-heating halogen lamps, the laser-diode-heated floating-zone furnace holds a higher maximum temperature and a steeper temperature gradient at the liquid-solid interface [29]. These advantages are more favorable during the process of single crystal growth [15,30]. In this study, the laser-diode-heated floating-zone furnace is equipped with five laser diodes with a wavelength of ∼975 nm and a power of ∼200 W each.…”

“…In this study, the laser-diode-heated floating-zone furnace is equipped with five laser diodes with a wavelength of ∼975 nm and a power of ∼200 W each. The shape of the laser beam is 4 mm (width) × 8 mm (height), and the working distances are ∼135 mm [30].…”

“…Finally, homogeneously densified seed and feed rods with a homogeneous composition distribution were obtained. We have grown bulk single crystals of a La 1.37 Sr 1.63 Mn 2 O 7 compound with a laser-diode-heated floating-zone furnace (Model: LD-FZ-5-200W-VPO-4 PC-UM, Crystal Systems Corporation, Japan) [30,34].…”