Exploring the critical behavior of the anomalous spin-glass transition in Ga1−xMnxS

Abstract

Single-crystalline Ga1−xMnxS is a quasi-two-dimensional system that exhibits an anomalous spin-glass transition temperature compared with the other well-known spin-glass systems. In contrast to the other known spin-glasses that all have three-dimensional structures, our host chalcogenide GaS system is quasi-two-dimensional. Recent interest in utilizing spin-glass materials for applications in short-term, low-energy memory and processing power make this new 2-D system important for further exploration. We report on the critical behavior of the anomalous spin-glass transition in a single-crystalline Ga0.91Mn0.09S system. Using the scaling equation of state describing the spin-glass transition in Ga1−xMnxS, we obtained the relation χnl = C1H2/δ and extract the value δ = 5.5 ± 0.5 for this critical exponent as well as a value of ϕ = 4.8 for another critical exponent. We find this value of delta for the critical temperature Tc = 11.2 K, combined with the other critical exponents γ = 4.0 and β = 0.8 form a self-consistent description of the spin-glass transition in this unusual 2-D spin-glass system. Interestingly, these results represent convincing evidence that, despite Ga1−xMnxS having a quasi-two-dimensional structure, Ga1−xMnxS undergoes a true spin-glass transition and is related to the class of semiconducting spin-glass materials with short-range interactions. The spin-glass transition in Ga1−xMnxS is characterized by critical exponents similar to the three-dimensional spin-glass systems.