2018/03/14 by Yu Liu, V. N. Ivanovski, C. Petrovic · 1 citation
Physics and Astronomy · #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.96.144429
published as Physical Review B 96, 144429 (2017) · arXiv admin note: substantial text overlap with arXiv:1706.07324, arXiv:1803.04482
arxiv created 2018/03/14 · arxiv updated 2018/03/19
The critical properties of the single-crystalline van der Waals bonded ferromagnet Fe3-xGeTe2 were investigated by bulk dc magnetization around the paramagnetic (PM) to ferromagnetic (FM) phase transition. The Fe3-xGeTe2 single crystals grown by self-flux method with Fe deficiency x ≈ 0.36 exhibit bulk FM ordering below Tc = 152 K. The Mössbauer spectroscopy was used to provide information on defects and local atomic environment in such crystals. Critical exponents β= 0.372(4) with a critical temperature Tc = 151.25(5) K and γ= 1.265(15) with Tc = 151.17(12) K are obtained by the Kouvel-Fisher method whereas δ= 4.50(1) is obtained by a critical isotherm analysis at Tc = 151 K. These critical exponents obey the Widom scaling relation δ= 1+γ/β, indicating self-consistency of the obtained values. With these critical exponents the isotherm M(H) curves below and above the critical temperatures collapse into two independent universal branches, obeying the single scaling equation m = f_±(h), where m and h are renormalized magnetization and field, respectively. The exponents determined in this study are close to those calculated from the results of the renormalization group approach for a heuristic model of three-dimensional Heisenberg (d = 3, n = 3) spins coupled with the attractive long-range interactions between spins that decay as J(r)≈ r-(3+σ) with σ=1.89.