Dynamic susceptibility measurements at the spin-glass transition in the Zn_1−xMn_xIn₂Se₄semiconductor

Abstract

Measurements of the magnetic properties of the magnetic semiconductor Zn1−xMnxIn2Se4 for two Mn compositions (x = 0.87 and 1.00) are presented in this work. The localized Mn ions in the layered rhombohedral structure undergo a spin-freezing transition below 3.5 K. The frequency-dependent freezing temperature Tf varies as ΔTf/(TfΔlogω)≈0.022, indicating a spin-glass behaviour. From the frequency dependence of Tf, the validity of the critical slowing down associated with a true phase transition is tested. For T>Tc, the dynamic scaling of the imaginary component of ac susceptibility data yields the following set of critical parameters: zν = 9.7 ± 1.0, β = 1.18 ± 0.20 and Tc = 2.61 ± 0.06 K for x = 0.87 and zν = 10.7 ± 0.9, β = 1.20 ± 0.20 and Tc = 3.43 ± 0.01 K for x = 1.00. These values are in good agreement with reported values for other spin glasses.

Experimental evidence of the spin-glass transition in the diluted magnetic semiconductor Zn1−xMnxIn2Se4

“…However, the value determined for Zn 1−x Mn x In 2 Se 4 is consistent with commonly reported values for other spin glasses [21,28], irrespective of the crystalline structure of those spin-glass systems. Study of the dynamic properties has provided us with critical exponents which are consistent with those reported for other spin-glass like systems [26].…”

“…In a previous work [26], evidences of true spin-glass transition was determined from dynamic measurements (AC susceptibility). The maximum of the in-phase magnetic susceptibility (T f ) shows a relative variation per frequency decade of ( T f /T f )/ log f ≈ 0.022.…”

Dynamic response function in Ising systems belowTc

“…[7][8][9][10][11] One of the most important dynamic universality classes is that of the threedimensional Ising-like model with purely relaxational dynamics [model A (Ref. 12)].…”